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{{Short description|none}}
{{hatnote|"1,000", "Thousand", and "Chiliad" redirect here. For other uses, see [[1000 (disambiguation)]] or, for the military unit, see [[Chiliarchy]].}}
{{use dmy dates|date=January 2023}}
{{Infobox number
| number        = 1000
| divisor       = 1, 2, 4, 5, 8, 10, 20, 25, 40, 50, 100, 125, 200, 250, 500, 1000
| roman unicode = M, m, ↀ
| unicode       = ↀ
| Greek prefix  = [[Wiktionary:chilia-|chilia]]
| Latin prefix  = [[Wiktionary:milli-|milli]]
| lang1         = [[Tamil numerals|Tamil]]
| lang1 symbol  = ௲
| lang2         = [[Chinese numerals#Standard numbers|Chinese]]
| lang2 symbol  = 千
| lang3         = [[Punjabi language|Punjabi]]
| lang3 symbol  = ੧੦੦੦
|lang4         = [[Devanagari numerals#Standard numbers|Devanagari]]
| lang4 symbol = १०००
|lang5=[[Armenian numerals|Armenian]]|lang5 symbol=Ռ|lang6=[[Egyptian numerals|Egyptian hieroglyph]]|lang6 symbol=<span style="font-size:180%;">𓆼</span>}}
{{Wiktionary|thousand|1000}}

'''1000''' or '''one thousand''' is the [[natural number]] following [[999 (number)|999]] and preceding [[1001 (number)|1001]]. In most [[English-speaking countries]], it can be written with or without a comma or sometimes a period [[decimal mark#Digit grouping|separating]] the thousands digit: '''1,000'''.

A group of one thousand units is sometimes known, from [[Ancient Greek language|Ancient Greek]], as a '''chiliad'''.<ref>{{Cite web|url=https://www.merriam-webster.com/dictionary/chiliad|title=chiliad|publisher=[[Merriam-Webster]] | archive-url=https://archive.today/20220325170822/https://www.merriam-webster.com/dictionary/chiliad|archive-date=March 25, 2022|url-status=live}}</ref> A period of one thousand years may be known as a chiliad or, more often from [[Latin language|Latin]], as a [[millennium]]. The number 1000 is also sometimes described as a '''short thousand''' in medieval contexts where it is necessary to distinguish the [[Germanic languages|Germanic]] concept of 1200 as a [[long thousand]]. It is the first 4-digit [[integer]].

== Notation ==

* The decimal representation for one thousand is
** '''1000'''—a [[1 (number)|one]] followed by three [[0 (number)|zeros]], in the general notation;
** '''1 × 10<sup>3</sup>'''—in [[engineering notation]], which for this number coincides with:
** '''1 × 10<sup>3</sup>''' exactly—in [[scientific notation|scientific normalized exponential notation]];
** '''1 E+3''' exactly—in [[scientific notation#E notation|scientific E notation]].
* The [[SI prefix]] for a thousand units is "[[kilo-]]", abbreviated to "k"—for instance, a [[kilogram]] or "kg" is a thousand [[gram]]s. This is sometimes extended to non-SI contexts, such as "ka" ([[kiloannum]]) being used as a shorthand for periods of 1000 years. In [[computer science]], however, "kilo-" is used more loosely to mean 2 to the 10th power (1024).
* In the [[SI#SI writing style|SI writing style]], a [[non-breaking space]] can be used as a [[thousands separator]], i.e., to separate the digits of a number at every power of 1000.
* Multiples of thousands are occasionally represented by replacing their last three zeros with the letter "K" or "k": for instance, writing "$30k" for $30&nbsp;000 or denoting the [[Year 2000 problem|Y2K]] computer bug of the year 2000.
* A thousand units of [[currency]], especially [[dollar]]s or [[Pound (currency)|pound]]s, are colloquially called a ''grand''. In the United States, this is sometimes abbreviated with a "G" suffix.

== In Mathematics ==
A '''[[chiliagon]]''' is a 1000-sided [[polygon]].<ref name="Chilia">{{Cite OEIS|A195163|1000-gonal numbers: a(n) equal to n*(499*n - 498)}}</ref>

== Numbers in the range 1001–1999 ==

=== 1001 to 1099 ===

*'''[[1001 (number)|1001]]''' = [[sphenic number]] (7 × 11 × 13), [[pentagonal number]], [[pentatope number]], [[palindromic number]]
*'''1002''' = sphenic number, [[Mertens function]] zero, [[abundant number]], number of [[Partition function (number theory)|partitions]] of 22
*'''1003''' = the product of some prime ''p'' and the ''p''<sup>th</sup> prime, namely ''p'' = 17.
*'''1004''' = [[heptanacci number]]<ref name="Heptanacci numbers">{{Cite OEIS|A122189|Heptanacci numbers}}</ref>
*'''1005''' = Mertens function zero, decagonal pyramidal number<ref name="auto62">{{cite OEIS|A007585|10-gonal (or decagonal) pyramidal numbers}}</ref>
*'''1006''' = [[semiprime]], product of two distinct [[isolated prime]]s (2 and 503); [[unusual number]]; [[square-free number]]; number of [[composition (combinatorics)|composition]]s (ordered [[partition (number theory)|partition]]s) of 22 into squares; sum of two distinct [[pentatope number]]s (5 and 1001); number of undirected [[Hamiltonian path]]s in 4 by 5 [[square grid graph]];<ref>{{cite OEIS|A332307|Array read by antidiagonals: T(m,n) is the number of (undirected) Hamiltonian paths in the m X n grid graph|access-date=2023-01-08}}</ref> record gap between [[twin prime]]s;<ref>{{cite OEIS|A036063|Increasing gaps among twin primes: size}}</ref> number that is the sum of 7 positive 5th powers.<ref name="auto9">{{Cite OEIS|A003352|Numbers that are the sum of 7 positive 5th powers}}</ref> In decimal: [[equidigital number]]; when turned around, the number looks like a prime, 9001; its [[cube (algebra)|cube]] can be [[concatenated]] from other cubes, 1_0_1_8_1_0_8_216 ("_" indicates concatenation, 0 = 0<sup>3</sup>, 1 = 1<sup>3</sup>, 8 = 2<sup>3</sup>, 216 = 6<sup>3</sup>)<ref>{{cite OEIS|A061341|A061341 Numbers not ending in 0 whose cubes are concatenations of other cubes}}</ref>
*'''1007''' = number that is the sum of 8 positive 5th powers<ref>{{Cite OEIS|A003353|Numbers that are the sum of 8 positive 5th powers}}</ref>
*'''1008''' = divisible by the number of primes below it
*'''1009''' = smallest four-digit [[prime number|prime]], [[palindromic number|palindromic]] in bases 11, 15, 19, 24 and 28: (838<sub>11</sub>, 474<sub>15</sub>, 2F2<sub>19</sub>, 1I1<sub>24</sub>, 181<sub>28</sub>). It is also a [[Lucky prime#Lucky primes|Lucky prime]] and [[Chen prime]].
*'''1010''' = 10<sup>3</sup> + 10,<ref>{{cite OEIS|A034262|2=a(n) = n^3 + n}}</ref> Mertens function zero
*'''1011''' = the largest ''n'' such that 2<sup>n</sup> contains 101 and does not contain 11011, [[Harshad number]] in bases 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75 (and 202 other bases), number of partitions of 1 into reciprocals of positive integers <= 16 [[Egyptian fraction]]<ref name=A020473>{{cite OEIS|A020473|2=Egyptian fractions: number of partitions of 1 into reciprocals of positive integers <= n}}</ref>
*'''1012''' = [[ternary numeral system|ternary]] number, (32<sub>10</sub>) quadruple [[triangular number]] ([[triangular number]] is [[253 (number)|253]]),<ref>{{Cite OEIS|A046092|name=4 times triangular numbers: a(n) = 2*n*(n+1)|access-date=2023-10-10}}</ref> number of partitions of 1 into reciprocals of positive integers <= 17 [[Egyptian fraction]]<ref name=A020473/>
*'''1013''' = [[Sophie Germain prime]],<ref name="Sophie Germain">{{Cite OEIS|A005384|Sophie Germain primes p: 2p+1 is also prime}}</ref> [[centered square number]],<ref name="Centered square numbers">{{Cite OEIS|A001844|Centered square numbers}}</ref> Mertens function zero
*'''1014''' = 2<sup>10</sup>-10,<ref>{{cite OEIS|A000325|2=a(n) = 2^n - n}}</ref> Mertens function zero, sum of the nontriangular numbers between successive triangular numbers 78 and 91<ref>{{cite OEIS|A006002|2=a(n) = n*(n+1)^2/2}}</ref>
*'''1015''' = [[square pyramidal number]]<ref name="Square pyramidal numbers">{{Cite OEIS|A000330|Square pyramidal numbers}}</ref>
*'''1016''' = member of the [[Mian–Chowla sequence]],<ref name="Mian-Chowla">{{Cite OEIS|A005282|Mian-Chowla sequence}}</ref> [[stella octangula number]], number of surface points on a cube with edge-length 14<ref name="A005897" />
*'''1017''' = generalized triacontagonal number<ref>{{Cite OEIS|A316729|2=Generalized 30-gonal (or triacontagonal) numbers: m*(14*m - 13) with m = 0, +1, -1, +2, -2, +3, -3}}</ref>
*'''1018''' = Mertens function zero, 1018<sup>16</sup> + 1 is prime<ref>{{cite OEIS|A006313|Numbers n such that n^16 + 1 is prime}}</ref>
*'''1019''' = [[Sophie Germain prime]],<ref name="Sophie Germain" /> [[safe prime]],<ref name="Safe primes">{{Cite OEIS|A005385|Safe primes p: (p-1)/2 is also prime}}</ref> [[Chen prime]]
*'''1020''' = [[polydivisible number]]
*'''1021''' = [[twin prime]] with '''1019'''. It is also a [[Lucky number#Lucky primes|Lucky prime]].
*'''1022''' = [[Friedman number]]
*'''[[1023 (number)|1023]]''' = sum of five consecutive primes (193 + 197 + 199 + 211 + 223);<ref>{{Cite OEIS|A034964|Sums of five consecutive primes}}</ref> the number of [[three-dimensional space|three-dimensional]] [[polycube]]s with [[7 (number)|7]] cells;<ref>{{Cite OEIS|A000162|Number of 3-dimensional polyominoes (or polycubes) with n cells}}</ref> number of [[Simplex#Elements|elements]] in a [[9-simplex]]; highest number one can count to on one's fingers using binary; magic number used in [[Global Positioning System]] signals.
*'''[[1024 (number)|1024]]''' = 32<sup>2</sup> = 4<sup>5</sup> = 2<sup>10</sup>, the number of [[byte]]s in a [[kilobyte]] (in 1999, the [[International Electrotechnical Commission|IEC]] coined [[kibibyte]] to use for 1024 with kilobyte being 1000, but this convention has not been widely adopted). 1024 is the smallest 4-digit square and also a [[Friedman number]].
*'''1025''' = [[Proth number]] 2<sup>10</sup> + 1; member of [[Moser–de Bruijn sequence]], because its base-4 representation (100001<sub>4</sub>) contains only digits 0 and 1, or it's a sum of distinct powers of 4 (4<sup>5</sup> + 4<sup>0</sup>); [[Jacobsthal-Lucas number]]; hypotenuse of [[primitive Pythagorean triangle]]
*'''1026''' = sum of two distinct powers of 2 ([[1024 (number)|1024]] + [[2]])
*'''1027''' = sum of the squares of the first eight primes; can be written from base 2 to base 18 using only the digits 0 to 9.
*'''1028''' = sum of totient function for first 58 integers; can be written from base 2 to base 18 using only the digits 0 to 9; number of primes <= 2<sup>13</sup>.<ref name="auto3">{{cite OEIS|A007053|2=Number of primes <= 2^n}}</ref>
*'''1029''' = can be written from base 2 to base 18 using only the digits 0 to 9.
*'''1030''' = generalized heptagonal number
*'''1031''' = exponent and number of ones for the fifth base-10 [[repunit|repunit prime]],<ref>{{Cite OEIS|A004023|Indices of prime repunits: numbers n such that 11...111 (with n 1's)... is prime}}</ref> [[Sophie Germain prime]],<ref name="Sophie Germain" /> [[super-prime]], [[Chen prime]]
*'''1032''' = sum of two distinct powers of 2 ([[1024 (number)|1024]] + [[8]])
*'''1033''' = [[emirp]], [[twin prime]] with '''1031'''
*'''1034''' = sum of 12 positive 9th powers<ref>{{Cite OEIS|A004801|Sum of 12 positive 9th powers}}</ref>
*'''1035''' = 45th [[triangular number]],<ref name="Triangular number">{{Cite OEIS|A000217|Triangular numbers}}</ref> [[hexagonal number]]<ref name="Hexagonal number">{{Cite OEIS|A000384|Hexagonal numbers}}</ref>
*'''1036''' = central polygonal number<ref name="auto11">{{Cite OEIS|A000124|Central polygonal numbers (the Lazy Caterer's sequence): n(n+1)/2 + 1; or, maximal number of pieces formed when slicing a pancake with n cuts }}</ref>
*'''1037''' = number in E-toothpick sequence<ref>{{Cite OEIS|A161328|name=E-toothpick sequence (see Comments lines for definition)}}</ref>
*'''1038''' = [[parity (mathematics)|even]] [[integer]] that is an unordered sum of two [[prime number|primes]] in exactly ''n'' ways<ref>{{Cite OEIS|A023036|Smallest positive even integer that is an unordered sum of two primes in exactly n ways}}</ref>
*'''1039''' = [[Prime number|prime]] of the form 8n+7,<ref>{{Cite OEIS|A007522|Primes of the form 8n+7, that is, primes congruent to -1 mod 8|access-date=2023-10-10}}</ref> number of partitions of 30 that do not contain 1 as a part,<ref name="auto8">{{cite OEIS|A002865|Number of partitions of n that do not contain 1 as a part}}</ref> [[Chen prime]], [[Lucky prime]]
*'''1040''' = 4<sup>5</sup> + 4<sup>2</sup>: sum of distinct powers of 4.<ref name="auto6">{{Cite OEIS|A000695|Moser-de Bruijn sequence: sums of distinct powers of 4}}</ref> The number of pieces that could be seen in a 6 × 6 × 6× 6 Rubik's Tesseract.
*'''1041''' = sum of 11 positive 5th powers<ref>{{Cite OEIS|A003356|Numbers that are the sum of 11 positive 5th powers}}</ref>
*'''1042''' = sum of 12 positive 5th powers<ref name="auto">{{Cite OEIS|A003357|Numbers that are the sum of 12 positive 5th powers}}</ref>
*'''1043''' = number whose sum of [[parity (mathematics)|even]] digits and sum of [[parity (mathematics)|odd]] digits are even<ref>{{Cite OEIS|A036301|Numbers whose sum of even digits and sum of odd digits are equal}}</ref>
*'''1044''' = sum of distinct powers of 4<ref name="auto6"/>
*'''1045''' = [[octagonal number]]<ref>{{Cite OEIS|A000567|Octagonal numbers: n*(3*n-2). Also called star numbers}}</ref>
*'''1046''' = coefficient of f(q) (3rd order mock theta function)<ref>{{Cite OEIS|A000025|Coefficients of the 3rd-order mock theta function f(q)}}</ref>
*'''1047''' = number of ways to split a strict composition of 18 into contiguous subsequences that have the same sum<ref>{{Cite OEIS|A336130|Number of ways to split a strict composition of n into contiguous subsequences all having the same sum}}</ref>
*'''1048''' = number of partitions of 27 into [[squarefree number|squarefree]] parts<ref>{{Cite OEIS|A073576|Number of partitions of n into squarefree parts}}</ref>
*'''1049''' = [[Sophie Germain prime]],<ref name="Sophie Germain" /> [[highly cototient number]],<ref name="highly cototient">{{Cite OEIS|A100827|Highly cototient numbers: records for a(n) in A063741}}</ref> [[Chen prime]]
*'''1050''' = 1050<sub>8</sub> to [[decimal]] becomes a [[pronic number]] (552<sub>10</sub>),<ref>{{cite web | url=https://www.rapidtables.com/convert/number/base-converter.html?x=1050&sel1=3&sel2=10 | title=Base converter {{pipe}} number conversion }}</ref> number of parts in all partitions of 29 into distinct parts<ref name="auto46">{{cite OEIS|A015723|Number of parts in all partitions of n into distinct parts}}</ref>
*'''1051''' = [[centered pentagonal number]],<ref name="Centered pentagonal">{{Cite OEIS|A005891|Centered pentagonal numbers}}</ref> [[centered decagonal number]]
*'''1052''' = sum of 9 positive 6th powers<ref>{{Cite OEIS|A003365|Numbers that are the sum of 9 positive 6th powers}}</ref>
*'''1053''' = triangular matchstick number<ref name="auto5" />
*'''1054''' = [[centered triangular number]]<ref>{{Cite OEIS|A005448|2=	Centered triangular numbers: a(n) = 3*n*(n-1)/2 + 1}}</ref>
*'''1055''' = sum of 12 positive 6th powers<ref>{{Cite OEIS|A003368|Numbers that are the sum of 12 positive 6th powers}}</ref>
*'''1056''' = [[pronic number]]<ref name="pronic number">{{Cite OEIS|A002378|Oblong (or promic, pronic, or heteromecic) numbers}}</ref>
*'''1057''' = central polygonal number<ref>{{Cite OEIS|A002061|2=Central polygonal numbers: a(n) = n^2 - n + 1}}</ref>
*'''1058''' = sum of 4 positive 5th powers,<ref>{{Cite OEIS|A003349|Numbers that are the sum of 4 positive 5th powers}}</ref> area of a square with diagonal 46<ref name="area of a square with diagonal 2n">{{cite OEIS|A001105|2=a(n) = 2*n^2}}</ref>
*'''1059''' = number ''n'' such that n<sup>4</sup> is written in the form of a sum of four positive 4th powers<ref>{{Cite OEIS|A003294|Numbers k such that k^4 can be written as a sum of four positive 4th powers}}</ref>
*'''1060''' = sum of the first twenty-five primes from [[2]] through [[97 (number)|97]] (the number of primes less than [[100]]),<ref>{{Cite OEIS|A007504|Sum of the first n primes}}</ref> and sixth sum of 10 consecutive primes, starting with [[23 (number)|23]] through [[131 (number)|131]].<ref name="auto102">{{Cite OEIS|A127337|Numbers that are the sum of 10 consecutive primes}}</ref>
*'''1061''' = [[emirp]], [[twin prime]] with '''1063''', number of prime numbers between 1000 and [[10000 (number)|10000]] (or, number of four-digit primes in [[decimal]] representation)<ref>{{Cite OEIS|A006879|Number of primes with n digits.}}</ref>
*'''1062''' = number that is not the sum of two [[palindromes]]<ref name="auto10">{{Cite OEIS|A035137|Numbers that are not the sum of 2 palindromes (where 0 is considered a palindrome)}}</ref>
*'''1063''' = [[super-prime]], sum of seven consecutive primes (137 + 139 + 149 + 151 + 157 + 163 + 167); near-wall-sun-sun prime.<ref>{{Cite OEIS|A347565|Primes p such that A241014(A000720(p)) is +1 or -1}}</ref> It is also a [[twin prime]] with '''1061'''.
*'''1064''' = sum of two positive [[cube number|cubes]]<ref>{{Cite OEIS|A003325|Numbers that are the sum of 2 positive cubes}}</ref>
*'''1065''' = generalized duodecagonal<ref>{{Cite OEIS|A195162|2=Generalized 12-gonal numbers: k*(5*k-4) for k = 0, +-1, +-2, ...}}</ref>
*'''1066''' = number whose sum of their [[divisors]] is a [[square number|square]]<ref>{{Cite OEIS|A006532|Numbers whose sum of divisors is a square}}</ref>
*'''1067''' = number of strict [[integer]] [[fraction|partitions]] of 45 in which are empty or have smallest [[fraction|part]] not dividing the other ones<ref>{{Cite OEIS|A341450|Number of strict integer partitions of n that are empty or have smallest part not dividing all the others}}</ref>
*'''1068''' = number that is the sum of 7 positive 5th powers,<ref name="auto9"/> total number of parts in all partitions of 15<ref name="auto16">{{cite OEIS|A006128|Total number of parts in all partitions of n. Also, sum of largest parts of all partitions of n}}</ref>
*'''1069''' = [[emirp]]<ref name="auto4">{{Cite OEIS|A006567|Emirps (primes whose reversal is a different prime)}}</ref>
*'''1070''' = number that is the sum of 9 positive 5th powers<ref name="auto2">{{Cite OEIS|A003354|Numbers that are the sum of 9 positive 5th powers}}</ref>
*'''1071''' = [[heptagonal number]]<ref name="heptagonal number">{{Cite OEIS|A000566|Heptagonal numbers (or 7-gonal numbers): n*(5*n-3)/2}}</ref>
*'''1072''' = [[centered heptagonal number]]<ref name="centered heptagonal number">{{Cite OEIS|A069099|Centered heptagonal numbers}}</ref>
*'''1073''' = number that is the sum of 12 positive 5th powers<ref name="auto" />
*'''1074''' = number that is not the sum of two [[palindromes]]<ref name="auto10" />
*'''1075''' = number non-sum of two [[palindromes]]<ref name="auto10" />
*'''1076''' = number of strict trees weight 11<ref>{{Cite OEIS|A273873|Number of strict trees of weight n}}</ref>
*'''1077''' = number where [[7]] outnumbers every other digit in the number<ref>{{Cite OEIS|A292457|Numbers where 7 outnumbers any other digit}}</ref>
*'''1078''' = [[Euler number|Euler]] transform of negative [[integers]]<ref>{{Cite OEIS|A073592|Euler transform of negative integers}}</ref>
*'''1079''' = every positive integer is the sum of at most 1079 tenth powers.
*'''1080''' = pentagonal number,<ref name="Pentagonal number">{{Cite OEIS|A000326|Pentagonal numbers}}</ref> [[largely composite number]]<ref name="OEIS-A067128">{{Cite OEIS|A067128|Ramanujan's largely composite numbers}}</ref>
*'''1081''' = 46th [[triangular number]],<ref name="Triangular number" /> member of [[Padovan sequence]]<ref name="Padovan sequence">{{Cite OEIS|A000931|Padovan sequence}}</ref>
*'''1082''' = central polygonal number<ref name="auto11"/>
*'''1083''' = three-quarter [[square number|square]],<ref>{{Cite OEIS|A077043|2="Three-quarter squares": a(n) = n^2 - A002620(n)}}</ref> number of partitions of 53 into prime parts<ref>{{Cite OEIS|A000607|Number of partitions of n into prime parts}}</ref>
*'''1084''' = [[3|third]] spoke of a hexagonal spiral,<ref>{{Cite OEIS|A056107|Third spoke of a hexagonal spiral}}</ref> [[oeis:A006316|1084<sup>64</sup> + 1 is prime]]
*'''1085''' = number of partitions of ''n'' into distinct [[fraction|parts]] > or = [[2]]<ref>{{Cite OEIS|A025147|2=Number of partitions of n into distinct parts >= 2}}</ref>
*'''1086''' = [[Smith number]],<ref>{{Cite OEIS|A006753|Smith numbers}}</ref> sum of totient function for first 59 integers
*'''1087''' = super-prime, [[cousin prime]], [[lucky prime]]<ref>{{Cite OEIS|A031157|Numbers that are both lucky and prime}}</ref>
*'''1088''' = octo-[[triangular number]], ([[triangular number]] result being [[136 (number)|136]])<ref>{{Cite OEIS|A033996|2=8 times triangular numbers: a(n) = 4*n*(n+1)}}</ref> sum of two distinct powers of 2, ([[1024 (number)|1024]] + [[64 (number)|64]])<ref>{{Cite OEIS|A018900|Sums of two distinct powers of 2}}</ref> number that is divisible by exactly seven [[primes]] with the inclusion of [[multiplication|multiplicity]]<ref>{{Cite OEIS|A046308|Numbers that are divisible by exactly 7 primes counting multiplicity}}</ref>
*'''[[1089 (number)|1089]]''' = 33<sup>2</sup>, [[nonagonal number]], [[centered octagonal number]], first natural number whose digits in its decimal representation get reversed when multiplied by 9.<ref>{{Cite OEIS|A001232|2=Numbers n such that 9*n = (n written backwards)}}</ref>
*'''1090''' = sum of 5 positive 5th powers<ref>{{Cite OEIS|A003350|Numbers that are the sum of 5 positive 5th powers}}</ref>
*'''1091''' = [[cousin prime]] and [[twin prime]] with '''1093'''
*'''1092''' = divisible by the number of primes below it
*'''[[1093 (number)|1093]]''' = the smallest [[Wieferich prime]] (the only other known [[Wieferich prime]] is 3511<ref>Wells, D. ''[[The Penguin Dictionary of Curious and Interesting Numbers]]'' London: Penguin Group. (1987): 163</ref>), [[twin prime]] with '''1091''' and [[star number]]<ref name="Centered 12-gonal numbers">{{Cite OEIS|A003154|Centered 12-gonal numbers. Also star numbers}}</ref>
*'''1094''' = sum of 9 positive 5th powers,<ref name="auto2" /> [[oeis:A006316|1094<sup>64</sup> + 1 is prime]]
*'''1095''' = sum of 10 positive 5th powers,<ref>{{Cite OEIS|A003355|Numbers that are the sum of 10 positive 5th powers}}</ref> number that is not the sum of two [[palindromes]]
*'''1096''' = hendecagonal number,<ref>{{Cite OEIS|A051682|2=11-gonal (or hendecagonal) numbers: a(n) = n*(9*n-7)/2}}</ref> number of strict solid partitions of 18<ref name="auto43">{{cite OEIS|A323657|Number of strict solid partitions of n}}</ref>
*'''1097''' = [[emirp]],<ref name="auto4" /> [[Chen prime]]
*'''1098''' = multiple of 9 containing digit 9 in its [[decimal|base-10]] representation<ref>{{Cite OEIS|A121029|Multiples of 9 containing a 9 in their decimal representation}}</ref>
*'''1099''' = number where 9 outnumbers every other digit<ref>{{Cite OEIS|A292449|Numbers where 9 outnumbers any other digit}}</ref>

=== 1100 to 1199 ===

*'''1100''' = number of partitions of 61 into distinct squarefree parts<ref>{{cite OEIS|A087188|number of partitions of n into distinct squarefree parts}}</ref>
*'''1101''' = pinwheel number<ref name="Pinwheel">{{cite OEIS|A059993|Pinwheel numbers: 2*n^2 + 6*n + 1}}</ref>
*'''1102''' = sum of totient function for first 60 integers
*'''1103''' = [[Sophie Germain prime]],<ref name="Sophie Germain" /> [[balanced prime]]<ref name="Balanced prime">{{Cite OEIS|A006562|Balanced primes}}</ref>
*'''1104''' = [[Keith number]]<ref name="Keith number">{{Cite OEIS|A007629|Repfigit (REPetitive FIbonacci-like diGIT) numbers (or Keith numbers)}}</ref>
*'''[[1105 (number)|1105]]''' = 33<sup>2</sup> + 4<sup>2</sup> = 32<sup>2</sup> + 9<sup>2</sup> = 31<sup>2</sup> + 12<sup>2</sup> = 23<sup>2</sup> + 24<sup>2</sup>, [[Carmichael number]],<ref>{{Cite web|url=https://oeis.org/A002997|title=Sloane's A002997 : Carmichael numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> [[magic constant]] of ''n'' × ''n'' normal [[magic square]] and [[Eight queens puzzle|''n''-queens problem]] for ''n'' = 13, [[decagonal number]],<ref name="Decagonal">{{Cite web|url=https://oeis.org/A001107|title=Sloane's A001107 : 10-gonal (or decagonal) numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> centered square number,<ref name="Centered square numbers" /> [[Fermat pseudoprime]]<ref name="auto93">{{cite OEIS|A001567|Fermat pseudoprimes to base 2, also called Sarrus numbers or Poulet numbers}}</ref>
*'''1106''' = number of regions into which the plane is divided when drawing 24 ellipses<ref name="auto91">{{cite OEIS|A051890|2*(n^2 - n + 1)}}</ref>
*'''1107''' = number of non-isomorphic strict T<sub>0</sub> multiset partitions of weight 8<ref>{{cite OEIS|A319560|Number of non-isomorphic strict T_0 multiset partitions of weight n}}</ref>
*'''1108''' = [[oeis:A006316|number k such that k<sup>64</sup> + 1 is prime]]
*'''1109''' = Friedlander-Iwaniec prime,<ref name="auto12">{{cite OEIS|A028916|Friedlander-Iwaniec primes: Primes of form a^2 + b^4}}</ref> [[Chen prime]]
*'''1110''' = k such that 2<sup>k</sup> + 3 is prime<ref>{{cite OEIS|A057732|Numbers k such that 2^k + 3 is prime}}</ref>
*'''1111''' = 11 × 101, palindrome that is a product of two palindromic primes,<ref name="auto29">{{cite OEIS|A046376|Palindromes with exactly 2 palindromic prime factors (counted with multiplicity), and no other prime factors}}</ref> [[repunit]]<ref>{{Cite web |title=A002275 - OEIS |url=https://oeis.org/search?q=A002275&language=english&go=Search |access-date=2024-03-08 |website=oeis.org}}</ref>
*'''1112''' = k such that 9<sup>k</sup> - 2 is a prime<ref>{{cite OEIS|A128455|Numbers k such that 9^k - 2 is a prime}}</ref>
*'''1113''' = number of strict partions of 40<ref name="auto20">{{cite OEIS|A000009|Expansion of Product_{m > 0} (1 + x^m); number of partitions of n into distinct parts; number of partitions of n into odd parts}}</ref>
*'''1114''' = number of ways to write 22 as an orderless product of orderless sums<ref name="auto79">{{cite OEIS|A318949|Number of ways to write n as an orderless product of orderless sums}}</ref>
*'''1115''' = number of partitions of 27 into a prime number of parts<ref name="auto70">{{cite OEIS|A038499|Number of partitions of n into a prime number of parts}}</ref>
*'''1116''' = divisible by the number of primes below it
*'''1117''' = number of diagonally symmetric polyominoes with 16 cells,<ref name="auto23">{{cite OEIS|A006748|Number of diagonally symmetric polyominoes with n cells}}</ref> [[Chen prime]]
*'''1118''' = number of unimodular 2 × 2 matrices having all terms in {0,1,...,21}<ref name="auto54">{{cite OEIS|A210000|Number of unimodular 2 X 2 matrices having all terms in {0,1,...,n}<nowiki />}}</ref>
*'''1119''' = number of [[bipartite graphs]] with 9 nodes<ref>{{cite OEIS|A033995|Number of bipartite graphs with n nodes}}</ref>
*'''1120''' = [[oeis:A006316|number k such that k<sup>64</sup> + 1 is prime]]
*'''1121''' = number of squares between 34<sup>2</sup> and 34<sup>4</sup>.<ref name="auto40">{{cite OEIS|A028387|n + (n+1)^2}}</ref>
*'''1122''' = pronic number,<ref name="pronic number" /> divisible by the number of primes below it
*'''1123''' = [[balanced prime]]<ref name="Balanced prime" />
*'''1124''' = [[Leyland number]]<ref name=A076980>{{Cite OEIS|A076980|2=Leyland numbers: 3, together with numbers expressible as n^k + k^n nontrivially, i.e., n,k > 1 (to avoid n = (n-1)^1 + 1^(n-1))}}</ref> using 2 & 10 (2<sup>10</sup> + 10<sup>2</sup>), spy number
*'''1125''' = [[Achilles number]]
*'''1126''' = number of 2 × 2 non-singular integer matrices with entries from {0, 1, 2, 3, 4, 5}<ref>{{cite OEIS|A062801|Number of 2 X 2 non-singular integer matrices with entries from {0,...,n}<nowiki />}}</ref>
*'''1127''' = maximal number of pieces that can be obtained by cutting an annulus with 46 cuts<ref name="auto73">{{cite OEIS|A000096|n*(n+3)/2}}</ref>
*'''1128''' = 47th [[triangular number]],<ref name="Triangular number" /> 24th hexagonal number,<ref name="Hexagonal number" /> divisible by the number of primes below it ([[188 (number)|188]] × [[6]]).<ref>{{Cite OEIS |A057809 |Numbers n such that pi(n) divides n. |access-date=2024-05-23 }}</ref> 1128 is the dimensional representation of the largest [[vertex operator algebra]] with [[central charge]] of 24, ''D''<sub>24</sub>.<ref>{{Cite journal |last1=Van Ekeren |first1=Jethro |last2=Lam |first2=Ching Hung |last3=Möller |first3=Sven |last4=Shimakura |first4=Hiroki |title=Schellekens' list and the very strange formula |url=https://www.sciencedirect.com/science/article/abs/pii/S0001870821000050 |journal=[[Advances in Mathematics]] |volume=380 |publisher=[[Elsevier]] |location=Amsterdam |year=2021 |pages=1–34 (107567) |doi=10.1016/j.aim.2021.107567 |mr=4200469 |zbl=1492.17027 |s2cid=218870375 |arxiv=2005.12248 }}</ref>
*'''1129''' = number of lattice points inside a circle of radius 19<ref name="auto22">{{cite OEIS|A000328}}</ref>
*'''1130''' = skiponacci number<ref name="auto25">{{cite OEIS|A001608|Perrin sequence}}</ref>
*'''1131''' = number of edges in the [[:File:Hexagonal triangle.png|hexagonal triangle]] T(26)<ref name="auto60">{{cite OEIS|A140091|3*n*(n + 3)/2}}</ref>
*'''1132''' = number of simple unlabeled graphs with 9 nodes of 2 colors whose components are complete graphs<ref>{{cite OEIS|A005380}}</ref>
*'''1133''' = number of primitive subsequences of {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15}<ref>{{cite OEIS|A051026|Number of primitive subsequences of 1, 2, ..., n}}</ref>
*'''1134''' = divisible by the number of primes below it, triangular matchstick number<ref name="auto5">{{cite OEIS|A045943|Triangular matchstick numbers: 3*n*(n+1)/2|access-date=2022-06-02}}</ref>
*'''1135''' = [[centered triangular number]]<ref name="auto52">{{cite OEIS|A005448|Centered triangular numbers: 3n(n-1)/2 + 1}}</ref>
*'''1136''' = number of [https://mathworld.wolfram.com/IndependentVertexSet.html independent vertex sets] and [https://mathworld.wolfram.com/VertexCover.html vertex covers] in the 7-[https://mathworld.wolfram.com/SunletGraph.html sunlet graph]<ref>{{cite OEIS|A080040|2*a(n-1) + 2*a(n-2) for n > 1}}</ref>
*'''1137''' = sum of values of vertices at level 5 of the hyperbolic Pascal pyramid<ref>{{cite OEIS|A264237|Sum of values of vertices at level n of the hyperbolic Pascal pyramid}}</ref>
*'''1138''' = recurring number in the works of [[George Lucas]] and his companies, beginning with his first feature film – ''[[THX 1138]]''; particularly, a special code for Easter eggs on ''[[Star Wars]]'' DVDs.
*'''1139''' = [[wiener index]] of the [[windmill graph]] D(3,17)<ref name="auto90">{{cite OEIS|A033991|n*(4*n-1)}}</ref>
*'''1140''' = [[tetrahedral number]]<ref name="Tetrahedral nu">{{Cite web|url=https://oeis.org/A000292|title=Sloane's A000292 : Tetrahedral numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref>
*'''1141''' = 7-Knödel number<ref name="auto21">{{cite OEIS|A208155|7-Knödel numbers}}</ref>
*'''1142''' = n such that n<sup>32</sup> + 1 is prime,<ref name="auto51">{{cite OEIS|A006315|Numbers n such that n^32 + 1 is prime}}</ref> spy number
*'''1143''' = number of set partitions of 8 elements with 2 connectors<ref>{{cite OEIS|A185982|Triangle read by rows: number of set partitions of n elements with k connectors}}</ref>
*'''1144''' is not the sum of a pair of twin primes<ref name="auto99">{{cite OEIS|A007534|Even numbers that are not the sum of a pair of twin primes}}</ref>
*'''1145''' = 5-[[Knödel number]]<ref name="auto14">{{cite OEIS|A050993|5-Knödel numbers}}</ref>
*'''1146''' is not the sum of a pair of twin primes<ref name="auto99"/>
*'''1147''' = 31 × 37 (a product of 2 successive primes)<ref>{{cite OEIS|A006094|Products of 2 successive primes}}</ref>
*'''1148''' is not the sum of a pair of twin primes<ref name="auto99"/>
*'''1149''' = a product of two palindromic primes<ref>{{cite OEIS|A046368|Products of two palindromic primes}}</ref>
*'''1150''' = number of 11-iamonds without bilateral symmetry.<ref>{{Cite web|url=https://number.academy/1150|title=1150 (number)|website=The encyclopedia of numbers}}</ref>
*'''1151''' = first prime following a [[prime gap]] of 22,<ref name="Prime gap">{{Cite web|url=https://oeis.org/A000101|title=Sloane's A000101 : Increasing gaps between primes (upper end)|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-07-10}}</ref> [[Chen prime]]
*'''1152''' = [[highly totient number]],<ref name="highly totient">{{Cite web|url=https://oeis.org/A097942|title=Sloane's A097942 : Highly totient numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> [[3-smooth]] number (2<sup>7</sup>×3<sup>2</sup>), area of a square with diagonal 48,<ref name="area of a square with diagonal 2n"/> [[Achilles number]]
*'''1153''' = [[super-prime]], [[Proth prime]]<ref name="Proth prime">{{Cite web|url=https://oeis.org/A080076|title=Sloane's A080076 : Proth primes|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref>
*'''1154''' = 2 × 24<sup>2</sup> + 2 = number of points on surface of tetrahedron with edge length 24<ref name="auto59">{{cite OEIS|
A005893|Number of points on surface of tetrahedron; coordination sequence for sodalite net (equals 2*n^2+2 for n > 0)}}</ref>
*'''1155''' = number of edges in the join of two cycle graphs, both of order 33,<ref name="auto89">{{cite OEIS|n*(n+2)}}</ref> product of first four odd primes (3*5*7*11)
*'''1156''' = 34<sup>2</sup>, [[octahedral number]],<ref name="Octahedral number">{{Cite web|url=https://oeis.org/A005900|title=Sloane's A005900 : Octahedral numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> centered pentagonal number,<ref name="Centered pentagonal" /> centered hendecagonal number.<ref>{{Cite web|url=https://oeis.org/A069125|title=Sloane's A069125 : a(n) = (11*n^2 - 11*n + 2)/2|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref>
*'''1157''' = smallest number that can be written as n^2+1 without any prime factors that can be written as a^2+1.<ref>{{Cite web|url=https://number.academy/1157|title=1157 (number)|website=The encyclopedia of numbers}}</ref>
*'''1158''' = number of points on surface of octahedron with edge length 17<ref name="auto61">{{cite OEIS|A005899|Number of points on surface of octahedron}}</ref>
*'''1159''' = member of the Mian–Chowla sequence,<ref name=Mian-Chowla /> a [[centered octahedral number]]<ref name="auto7">{{cite OEIS|A001845|Centered octahedral numbers (crystal ball sequence for cubic lattice)|access-date=2022-06-02}}</ref>
*'''1160''' = [[octagonal number]]<ref name="auto17">{{cite OEIS|A000567|Octagonal numbers: n*(3*n-2). Also called star numbers}}</ref>
*'''1161''' = sum of the first twenty-six primes
*'''1162''' = pentagonal number,<ref name="Pentagonal number" /> sum of totient function for first 61 integers
*'''1163''' = smallest prime > 34<sup>2</sup>.<ref name="auto57">{{cite OEIS|A007491|Smallest prime > n^2}}</ref> See [[Legendre's conjecture]]. [[Chen prime]].
*'''1164''' = number of chains of multisets that partition a normal multiset of weight 8, where a multiset is normal if it spans an initial interval of positive integers<ref>{{cite OEIS|A055887|Number of ordered partitions of partitions}}</ref>
*'''1165''' = 5-[[Knödel number]]<ref name="auto14"/>
*'''1166''' = heptagonal pyramidal number<ref name="auto82">{{cite OEIS|A002413|Heptagonal (or 7-gonal) pyramidal numbers}}</ref>
*'''1167''' = number of rational numbers which can be constructed from the set of integers between 1 and 43<ref name="auto56">{{cite OEIS|A018805}}</ref>
*'''1168''' = antisigma(49)<ref>{{cite OEIS|A024816|Antisigma(n): Sum of the numbers less than n that do not divide n}}</ref>
*'''1169''' = highly cototient number<ref name="highly cototient" />
*'''1170''' = highest possible score in a [[National Academic Quiz Tournaments]] (NAQT) match
*'''1171''' = super-prime
*'''1172''' = number of subsets of first 14 integers that have a sum divisible by 14<ref>{{Cite web|url=https://oeis.org/A063776|title=A063776 - OEIS|website=oeis.org}}</ref>
*'''1173''' = number of simple triangulation on a plane with 9 nodes<ref>{{Cite web|url=https://oeis.org/A000256|title=A000256 - OEIS|website=oeis.org}}</ref>
*'''1174''' = [[oeis:A332337|number of widely totally strongly normal compositions of 16]]
*'''1175''' = maximal number of pieces that can be obtained by cutting an annulus with 47 cuts<ref name="auto73"/>
*'''1176''' = 48th [[triangular number]]<ref name="Triangular number" />
*'''1177''' = heptagonal number<ref name="heptagonal number" />
*'''1178''' = number of surface points on a cube with edge-length 15<ref name="A005897" />
*'''1179''' = number of different permanents of binary 7*7 matrices<ref>{{Cite web|url=https://number.academy/1179|title=1179 (number)|website=The encyclopedia of numbers}}</ref>
*'''1180''' = smallest number of non-integral partitions into non-integral power >1000.<ref>{{Cite web|url=https://oeis.org/A000339|title=A000339 - OEIS|website=oeis.org}}</ref>
*'''1181''' = smallest k over 1000 such that 8*10^k-49 is prime.<ref>{{Cite web|url=https://oeis.org/A271269|title=A271269 - OEIS|website=oeis.org}}</ref>
*'''1182''' = number of necklaces possible with 14 beads of 2 colors (that cannot be turned over)<ref>{{Cite web|url=https://oeis.org/A000031|title=A000031 - OEIS|website=oeis.org}}</ref>
*'''1183''' = [[pentagonal pyramidal number]]
*'''1184''' = [[amicable number]] with 1210<ref>{{cite book |title=Number Story: From Counting to Cryptography |url=https://archive.org/details/numberstoryfromc00higg_612 |url-access=limited |last=Higgins |first=Peter |year=2008 |publisher=Copernicus |location=New York |isbn=978-1-84800-000-1 |page=[https://archive.org/details/numberstoryfromc00higg_612/page/n69 61] }}</ref>
*'''1185''' = number of partitions of 45 into pairwise relatively prime parts<ref name="auto71">{{cite OEIS|A051424|Number of partitions of n into pairwise relatively prime parts}}</ref>
*'''1186''' = number of diagonally symmetric [[polyominoes]] with 15 cells,<ref name="auto23"/> [[oeis:A000607|number of partitions of 54 into prime parts]]
*'''1187''' = safe prime,<ref name="Safe primes" /> [[Stern prime]],<ref name="Stern prime">{{Cite web|url=https://oeis.org/A042978|title=Sloane's A042978 : Stern primes|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> balanced prime,<ref name="Balanced prime" /> [[Chen prime]]
*'''1188''' = first 4 digit multiple of 18 to contain 18<ref>{{Cite web|url=https://oeis.org/A121038|title=A121038 - OEIS|website=oeis.org}}</ref>
*'''1189''' = number of squares between 35<sup>2</sup> and 35<sup>4</sup>.<ref name="auto40"/>
*'''1190''' = pronic number,<ref name="pronic number" /> number of cards to build a 28-tier house of cards<ref name="auto45">{{cite OEIS|A005449|Second pentagonal numbers: n*(3*n + 1)/2}}</ref>
*'''1191''' = 35<sup>2</sup> - 35 + 1 = H<sub>35</sub> (the 35th Hogben number)<ref name="auto77">{{cite OEIS|A002061|Central polygonal numbers: n^2 - n + 1}}</ref>
*'''1192''' = sum of totient function for first 62 integers
*'''1193''' = a number such that [[oeis:A059801|4<sup>1193</sup> - 3<sup>1193</sup> is prime]], [[Chen prime]]
*'''1194''' = number of permutations that can be reached with 8 moves of 2 bishops and 1 rook on a 3 × 3 chessboard<ref>{{Cite web|url=https://oeis.org/A175654|title=A175654 - OEIS|website=oeis.org}}</ref>
*'''1195''' = smallest four-digit number for which a<sup>−1</sup>(n) is an integer is a(n) is 2*a(n-1) - (-1)<sup>n</sup><ref>oeis.org/A062092</ref>
*'''1196''' = <math>\sum_{k=1}^{38} \sigma(k)</math><ref name="auto38">{{cite OEIS|A024916|Sum_1^n sigma(k)}}</ref>
*'''1197''' = pinwheel number<ref name="Pinwheel" />
*'''1198''' = centered heptagonal number<ref name="centered heptagonal number" />
*'''1199''' = area of the 20th [https://oeis.org/A080663/a080663.jpg conjoined trapezoid]<ref name="auto13">>{{cite OEIS|A080663|3*n^2 - 1}}</ref>

=== 1200 to 1299 ===

*'''1200''' = the '''[[long thousand]]''', ten "[[long hundred]]s" of 120 each, the traditional reckoning of large numbers in [[Germanic languages]], the number of households the [[Nielsen ratings]] sample,<ref>Meehan, Eileen R., ''Why TV is not our fault: television programming, viewers, and who's really in control'' Lanham, MD: Rowman & Littlefield, 2005</ref> [[oeis:A006316|number k such that k<sup>64</sup> + 1 is prime]]
*'''1201''' = centered square number,<ref name="Centered square numbers" /> [[super-prime]], [[centered decagonal number]]
*'''1202''' = [https://mathworld.wolfram.com/PlaneDivisionbyEllipses.html number of regions] the plane is divided into by 25 ellipses<ref name="auto91"/>
*'''1203''': first 4 digit number in the coordinating sequence for the (2,6,∞) tiling of the hyperbolic plane<ref>{{Cite web|url=https://oeis.org/A265070|title=A265070 - OEIS|website=oeis.org}}</ref>
*'''1204''': magic constant of a 7 × 7 × 7 magic cube<ref>{{Cite web|url=https://number.academy/1204|title=1204 (number)|website=The encyclopedia of numbers}}</ref>
*'''1205''' = number of partitions of 28 such that the number of odd parts is a part<ref name="auto72">{{cite OEIS|A240574|Number of partitions of n such that the number of odd parts is a part}}</ref>
*'''1206''' = 29-gonal number <ref>{{Cite web|url=https://oeis.org/A303815|title=A303815 - OEIS|website=oeis.org}}</ref>
*'''1207''' = composite [[de Polignac number]]<ref name="auto53">{{cite OEIS|A098237|Composite de Polignac numbers}}</ref>
*'''1208''' = number of strict chains of divisors starting with the superprimorial A006939(3)<ref>{{cite OEIS|A337070|Number of strict chains of divisors starting with the superprimorial A006939(n)}}</ref>
*'''1209''' = The product of all ordered non-empty subsets of {3,1} if {a,b} is a||b: 1209=1*3*13*31
*'''1210''' = amicable number with 1184<ref>Higgins, ibid.</ref>
*'''1211''' = composite [[de Polignac number]]<ref name="auto53"/>
*'''1212''' = <math>\sum_{k=0}^{17} p(k)</math>, where <math>p</math> is the number of partions of <math>k</math><ref>{{cite OEIS|A000070|Sum_{0..n} A000041(k)}}</ref>
*'''1213''' = [[emirp]]
*'''1214''' = sum of first 39 composite numbers,<ref name="auto94">{{cite OEIS|A053767|Sum of first n composite numbers}}</ref> spy number
*'''1215''' = number of edges in the [[:File:Hexagonal triangle.png|hexagonal triangle]] T(27)<ref name="auto60"/>
*'''1216''' = nonagonal number<ref name="Nonagonal number">{{Cite web|url=https://oeis.org/A001106|title=Sloane's A001106 : 9-gonal (or enneagonal or nonagonal) numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref>
*'''1217''' = [[super-prime]], Proth prime<ref name="Proth prime" />
*'''1218''' = triangular matchstick number<ref name="auto5"/>
*'''1219''' = [[Mertens function]] zero, [[centered triangular number]]<ref name="auto52"/>
*'''1220''' = Mertens function zero, number of binary vectors of length 16 containing no singletons<ref name="auto50">{{cite OEIS|A006355|Number of binary vectors of length n containing no singletons}}</ref>
*'''1221''' = product of the first two digit, and three digit repdigit
*'''1222''' = [[hexagonal pyramidal number]]
*'''1223''' = [[Sophie Germain prime]],<ref name="Sophie Germain" /> balanced prime, 200th prime number<ref name="Balanced prime" />
*'''1224''' = number of edges in the join of two cycle graphs, both of order 34<ref name="auto89"/>
*'''1225''' = 35<sup>2</sup>, 49th [[triangular number]],<ref name="Triangular number" /> 2nd nontrivial [[square triangular number]],<ref>{{Cite web|url=https://oeis.org/A001110|title=Sloane's A001110 : Square triangular numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> 25th [[hexagonal number]],<ref name="Hexagonal number" /> and the smallest number >1 to be all three.<ref>{{Cite web |title=A046177 - OEIS |url=https://oeis.org/A046177 |access-date=2024-12-18 |website=oeis.org}}</ref> Additionally a centered octagonal number,<ref name="Centered octagonal number">{{Cite web|url=https://oeis.org/A016754|title=Sloane's A016754 : Odd squares: a(n) = (2n+1)^2. Also centered octagonal numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> icosienneagonal,<ref>{{cite OEIS|A303815|Generalized 29-gonal (or icosienneagonal) numbers}}</ref> hexacontagonal,<ref>{{cite OEIS|A249911|60-gonal (hexacontagonal) numbers}}</ref> and hecatonicositetragonal (124-gonal) number, and the sum of 5 consecutive odd cubes (1³ + 3³ + 5³ + 7³ + 9³)
*'''1226''' = number of rooted identity trees with 15 nodes <ref>{{Cite web|url=https://oeis.org/A004111|title=A004111 - OEIS|website=oeis.org}}</ref>
*'''1227''' = smallest number representable as the sum of 3 triangular numbers in 27 ways<ref>{{Cite web|url=https://oeis.org/A061262|title=A061262 - OEIS|website=oeis.org}}</ref>
*'''1228''' = sum of totient function for first 63 integers
*'''1229''' = [[Sophie Germain prime]],<ref name="Sophie Germain" /> number of primes under 10,000, [[emirp]]
*'''1230''' = the Mahonian number: T(9, 6)<ref name="A008302">{{cite OEIS|A008302|Triangle of Mahonian numbers T(n,k): coefficients in expansion of Product{0..n-1} (1 + x + ... + x^i), where k ranges from 0 to A000217(n-1). Also enumerates permutations by their major index}}</ref>
*'''1231''' = smallest mountain emirp, as 121, smallest mountain number is 11 × 11
*'''1232''' = number of labeled ordered set of partitions of a 7-set into odd parts<ref>{{Cite web|url=https://oeis.org/A006154|title=A006154 - OEIS|website=oeis.org}}</ref>
*'''1233''' = 12<sup>2</sup> + 33<sup>2</sup>
*'''[[1234 (number)|1234]]''' = number of parts in all partitions of 30 into distinct parts,<ref name="auto46"/> smallest whole number containing all numbers from 1 to 4
*'''1235''' = excluding duplicates, contains the first four Fibonacci numbers <ref>{{Cite web|url=https://oeis.org/A000045|title=A000045 - OEIS|website=oeis.org}}</ref>
*'''1236''' = 617 + 619: sum of twin prime pair<ref name="auto48">{{cite OEIS|A054735|Sums of twin prime pairs}}</ref>
*'''1237''' = prime of the form 2p-1
*'''1238''' = number of partitions of 31 that do not contain 1 as a part<ref name="auto8"/>
*'''1239''' = toothpick number in 3D<ref>{{Cite web|url=https://oeis.org/A160160|title=A160160 - OEIS|website=oeis.org}}</ref>
*'''1240''' = square pyramidal number<ref name="Square pyramidal numbers" />
*'''1241''' = [[centered cube number]],<ref>{{Cite web|url=https://oeis.org/A005898|title=Sloane's A005898 : Centered cube numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> spy number
*'''1242''' = decagonal number<ref name="Decagonal" />
*'''1243''' = composite [[de Polignac number]]<ref name="auto53"/>
*'''1244''' = number of complete partitions of 25<ref>{{cite OEIS|A126796|Number of complete partitions of n}}</ref>
*'''1245''' = Number of labeled spanning intersecting set-systems on 5 vertices.<ref>oeis.org/A305843</ref>
*'''1246''' = number of partitions of 38 such that no part occurs more than once<ref>{{Cite web|url=https://oeis.org/A007690|title=A007690 - OEIS|website=oeis.org}}</ref>
*'''1247''' = pentagonal number<ref name="Pentagonal number" />
*'''1248''' = the first four powers of 2 concatenated together
*'''1249''' = emirp, [[trimorphic number]]<ref>{{Cite web|url=https://oeis.org/A033819|title=Sloane's A033819 : Trimorphic numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref>
*'''1250''' = area of a square with diagonal 50<ref name="area of a square with diagonal 2n"/>
*'''1251''' = 2 × 25<sup>2</sup> + 1 = number of different 2 × 2 determinants with integer entries from 0 to 25<ref name="auto32">{{cite OEIS|A058331|2*n^2 + 1}}</ref>
*'''1252''' = 2 × 25<sup>2</sup> + 2 = number of points on surface of tetrahedron with edgelength 25<ref name="auto59"/>
*'''1253''' = number of partitions of 23 with at least one distinct part<ref name="auto66">{{cite OEIS|A144300|Number of partitions of n minus number of divisors of n}}</ref>
*'''1254''' = number of partitions of 23 into relatively prime parts<ref>{{cite OEIS|A000837|Number of partitions of n into relatively prime parts. Also aperiodic partitions.}}</ref>
*'''1255''' = Mertens function zero, number of ways to write 23 as an orderless product of orderless sums,<ref name="auto79"/> number of partitions of 23<ref name="auto35">{{cite OEIS|A000041|a(n) is the number of partitions of n (the partition numbers)}}</ref>
*'''1256''' = 1 × 2 × (5<sup>2</sup>)<sup>2</sup> + 6,<ref name="ReferenceA">{{cite OEIS|A193757|Numbers which can be written with their digits in order and using only a plus and a squaring operator}}</ref> Mertens function zero
*'''1257''' = number of lattice points inside a circle of radius 20<ref name="auto22"/>
*'''1258''' = 1 × 2 × (5<sup>2</sup>)<sup>2</sup> + 8,<ref name="ReferenceA"/> Mertens function zero
*'''1259''' = [[highly cototient number]]<ref name="highly cototient" />
*'''1260''' = the 16th [[highly composite number]],<ref name="Highly composite">{{Cite web|url=https://oeis.org/A002182|title=Sloane's A002182 : Highly composite numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> pronic number,<ref name="pronic number" /> the smallest [[vampire number]],<ref name="Vampire number">{{Cite web|url=https://oeis.org/A014575|title=Sloane's A014575 : Vampire numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> sum of totient function for first 64 integers, number of strict partions of 41<ref name="auto20"/> and appears twice in the [[Book of Revelation]]
*'''1261''' = star number,<ref name="Centered 12-gonal numbers" /> Mertens function zero
*'''1262''' = maximal number of regions the plane is divided into by drawing 36 circles<ref name="auto27">{{cite OEIS|A014206|n^2 + n + 2}}</ref>
*'''1263''' = rounded total surface area of a regular tetrahedron with edge length 27<ref name="auto74">{{cite OEIS|A070169|Rounded total surface area of a regular tetrahedron with edge length n}}</ref>
*'''1264''' = sum of the first 27 primes
*'''1265''' = number of rooted trees with 43 vertices in which vertices at the same level have the same degree<ref name="auto28">{{cite OEIS|A003238|Number of rooted trees with n vertices in which vertices at the same level have the same degree}}</ref>
*'''1266''' = centered pentagonal number,<ref name="Centered pentagonal" /> Mertens function zero
*'''1267''' = 7-Knödel number<ref name="auto21"/>
*'''1268''' = number of partitions of 37 into prime power parts<ref name="auto87">{{cite OEIS|A023894|Number of partitions of n into prime power parts}}</ref>
*'''1269''' = least number of triangles of the [[Spiral of Theodorus]] to complete 11 revolutions<ref name="auto85">{{cite OEIS|A072895|Least k for the Theodorus spiral to complete n revolutions}}</ref>
*'''1270''' = 25 + 24×26 + 23×27,<ref>{{cite OEIS|A100040|2*n^2 + n - 5}}</ref> Mertens function zero
*'''1271''' = sum of first 40 composite numbers<ref name="auto94"/>
*'''1272''' = sum of first 41 nonprimes<ref name="ReferenceB">{{cite OEIS|A051349|Sum of first n nonprimes}}</ref>
*'''1273''' = 19 × 67 = 19 × prime(19)<ref name="cite OEIS|A033286|n * primen">{{cite OEIS|A033286|n * prime(n)}}</ref>
*'''1274''' = [[oeis:A006002|sum of the nontriangular numbers between successive triangular numbers]]
*'''1275''' = 50th [[triangular number]],<ref name="Triangular number" /> equivalently the sum of the first 50 natural numbers
*'''1276''' = number of irredundant sets in the 25-cocktail party graph<ref name="auto34">{{cite OEIS|A084849|1 + n + 2*n^2}}</ref>
*'''1277''' = the start of a [[prime constellation]] of length 9 (a "prime nonuple")
*'''1278''' = number of Narayana's cows and calves after 20 years<ref name="auto98">{{cite OEIS|A000930|Narayana's cows sequence}}</ref>
*'''1279''' = Mertens function zero, [[Mersenne prime]] exponent
*'''1280''' = Mertens function zero, number of parts in all compositions of 9<ref>{{cite OEIS|A001792|(n+2)*2^(n-1)}}</ref>
*'''1281''' = [[octagonal number]]<ref name="auto17"/>
*'''1282''' = Mertens function zero, number of partitions of 46 into pairwise relatively prime parts<ref name="auto71"/>
*'''1283''' = safe prime<ref name="Safe primes" />
*'''1284''' = 641 + 643: sum of twin prime pair<ref name="auto48"/>
*'''1285''' = Mertens function zero, number of free [[nonomino]]es, number of parallelogram polyominoes with 10 cells.<ref>{{cite OEIS|A006958|Number of parallelogram polyominoes with n cells (also called staircase polyominoes, although that term is overused)}}</ref>
*'''1286''' = number of inequivalent connected planar figures that can be formed from five 1 X 2 rectangles (or dominoes) such that each pair of touching rectangles shares exactly one edge, of length 1, and the adjacency graph of the rectangles is a tree<ref>{{cite OEIS|A216492|Number of inequivalent connected planar figures that can be formed from n 1 X 2 rectangles (or dominoes) such that each pair of touching rectangles shares exactly one edge, of length 1, and the adjacency graph of the rectangles is a tree}}</ref>
*'''1287''' = <math>{13 \choose 5}</math><ref>{{cite OEIS|A007318|Pascal's triangle read by rows}}</ref>
*'''1288''' = heptagonal number<ref name="heptagonal number" />
*'''[[1289 (number)|1289]]''' = Sophie Germain prime,<ref name="Sophie Germain" /> Mertens function zero
*'''1290''' = <math>\frac{1289 + 1291}{2}</math>, average of a twin prime pair<ref>{{cite OEIS|A014574|Average of twin prime pairs}}</ref>
*'''1291''' = largest prime < 6<sup>4</sup>,<ref>{{cite OEIS|A173831|Largest prime < n^4}}</ref> Mertens function zero
*'''1292''' = number such that phi(1292) = phi(sigma(1292)),<ref>{{cite OEIS|A006872|Numbers k such that phi(k) equals phi(sigma(k))}}</ref> Mertens function zero
*'''1293''' = <math>\sum_{j=1}^n j \times prime(j)</math><ref>{{cite OEIS|A014285|Sum_{1..n} j*prime(j)}}</ref>
*'''1294''' = rounded volume of a regular octahedron with edge length 14<ref name="auto84">{{cite OEIS|A071400|Rounded volume of a regular octahedron with edge length n}}</ref>
*'''1295''' = number of edges in the join of two cycle graphs, both of order 35<ref name="auto89"/>
*'''1296''' = 36<sup>2</sup> = 6<sup>4</sup>, sum of the cubes of the first eight positive integers, the number of [[rectangle]]s on a normal 8 × 8 [[chessboard]], also the maximum font size allowed in Adobe InDesign, number of combinations of 2 characters(00-ZZ)
*'''1297''' = [[super-prime]], Mertens function zero, pinwheel number<ref name="Pinwheel" />
*'''1298''' = [[oeis:A000607|number of partitions of 55 into prime parts]]
*'''1299''' = Mertens function zero, number of partitions of 52 such that the smallest part is greater than or equal to number of parts<ref name="auto75">{{cite OEIS|A003114|Number of partitions of n into parts 5k+1 or 5k+4}}</ref>

=== 1300 to 1399 ===

*'''1300''' = Sum of the first 4 fifth powers, Mertens function zero, largest possible win margin in an [[NAQT]] match; smallest even odd-factor hyperperfect number
*'''1301''' = centered square number,<ref name="Centered square numbers" /> Honaker prime,<ref name="auto39">{{cite OEIS|A033548|Honaker primes: primes P(k) such that sum of digits of P(k) equals sum of digits of k}}</ref> number of trees with 13 unlabeled nodes<ref>{{cite OEIS|A000055|Number of trees with n unlabeled nodes}}</ref>
*'''1302''' = Mertens function zero, number of edges in the [[:File:Hexagonal triangle.png|hexagonal triangle]] T(28)<ref name="auto60"/>
*'''1303''' = prime of form 21n+1 and 31n+1<ref>{{Cite web|url=https://oeis.org/A124826|title=A124826 - OEIS|website=oeis.org}}</ref><ref>{{Cite web|url=https://oeis.org/A142005|title=A142005 - OEIS|website=oeis.org}}</ref>
*'''1304''' = sum of 1304<sub>6</sub> and 1304 <sub>9</sub> which is 328+976
*'''1305''' = triangular matchstick number<ref name="auto5"/>
*'''1306''' = Mertens function zero. In [[base 10]], raising the digits of 1306 to powers of successive integers equals itself: {{nowrap|1=1306 = 1<sup>1</sup> + 3<sup>2</sup> + 0<sup>3</sup> + 6<sup>4</sup>.}} [[135 (number)|135]], [[175 (number)|175]], [[518 (number)|518]], and [[598 (number)|598]] also have this property. [[Centered triangular number]].<ref name="auto52"/>
*'''1307''' = safe prime<ref name="Safe primes" />
*'''1308''' = sum of totient function for first 65 integers
*'''1309''' = the first [[sphenic number]] followed by two consecutive such number
*'''1310''' = smallest number in the middle of a set of three sphenic numbers
*'''1311''' = number of integer partitions of 32 with no part dividing all the others<ref name="auto30">{{cite OEIS|A338470|Number of integer partitions of n with no part dividing all the others}}</ref>
*'''1312''' = member of the Mian-Chowla sequence;<ref name=Mian-Chowla />
*'''1313''' = sum of all parts of all partitions of 14 <ref>{{Cite web|url=https://oeis.org/A066186|title=A066186 - OEIS|website=oeis.org}}</ref>
*'''1314''' = number of integer partitions of 41 whose distinct parts are connected<ref name="auto86">{{cite OEIS|A304716|Number of integer partitions of n whose distinct parts are connected}}</ref>
*'''1315''' = 10^(2n+1)-7*10^n-1 is prime.<ref>{{Cite web|url=https://oeis.org/A115073|title=A115073 - OEIS|website=oeis.org}}</ref>
*'''1316''' = Euler transformation of sigma(11)<ref>{{Cite web|url=https://oeis.org/A061256|title=A061256 - OEIS|website=oeis.org}}</ref>
*'''1317''' = 1317 Only odd four digit number to divide the concatenation of all number up to itself in base 25<ref>{{Cite web|url=https://oeis.org/A061954|title=A061954 - OEIS|website=oeis.org}}</ref>
*'''1318'''<sup>512</sup> + 1 is prime,<ref>{{cite OEIS|A057465|Numbers k such that k^512 + 1 is prime}}</ref> Mertens function zero
*'''1319''' = safe prime<ref name="Safe primes" />
*'''1320''' = 659 + 661: sum of twin prime pair<ref name="auto48"/>
*'''1321''' = Friedlander-Iwaniec prime<ref name="auto12"/>
*'''1322''' = area of the 21st [https://oeis.org/A080663/a080663.jpg conjoined trapezoid]<ref name="auto13"/>
*'''1323''' = [[Achilles number]]
*'''1324''' = if D(n) is the nth representation of 1, 2 arranged lexicographically. 1324 is the first non-1 number which is D(D(x))<ref>{{Cite web|url=https://oeis.org/A030299|title=A030299 - OEIS|website=oeis.org}}</ref>
*'''1325''' = [[Markov number]],<ref name="Markov number">{{Cite web|url=https://oeis.org/A002559|title=Sloane's A002559 : Markoff (or Markov) numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> centered tetrahedral number<ref name="auto42">{{cite OEIS|A005894|Centered tetrahedral numbers}}</ref>
*'''1326''' = 51st [[triangular number]],<ref name="Triangular number" /> hexagonal number,<ref name="Hexagonal number" /> Mertens function zero
*'''1327''' = first prime followed by 33 consecutive composite numbers
*'''1328''' = sum of totient function for first 66 integers
*'''1329''' = Mertens function zero, sum of first 41 composite numbers<ref name="auto94"/>
*'''1330''' = tetrahedral number,<ref name="Tetrahedral nu"/> forms a [[Ruth–Aaron pair]] with 1331 under second definition
*'''1331''' = 11<sup>3</sup>, centered heptagonal number,<ref name="centered heptagonal number" /> forms a Ruth–Aaron pair with 1330 under second definition. This is the only non-trivial cube of the form ''x''<sup>2</sup> + ''x'' − 1, for ''x'' = 36.
*'''1332''' = pronic number<ref name="pronic number" />
*'''1333''' = 37<sup>2</sup> - 37 + 1 = H<sub>37</sub> (the 37th Hogben number)<ref name="auto77"/>
*'''1334''' = maximal number of regions the plane is divided into by drawing 37 circles<ref name="auto27"/>
*'''1335''' = pentagonal number,<ref name="Pentagonal number" /> Mertens function zero
*'''1336''' = sum of gcd(x, y) for 1 <= x, y <= 24,<ref>{{cite OEIS|A018806|Sum of gcd(x, y)}}</ref> Mertens function zero
*'''1337''' = Used in the novel form of spelling called [[leet]]. Approximate melting point of [[gold]] in [[kelvin]]s.
*'''1338''' = atomic number of the noble element of period 18,<ref>{{cite OEIS|A018227|Magic numbers: atoms with full shells containing any of these numbers of electrons are considered electronically stable}}</ref> Mertens function zero
*'''1339''' = First 4 digit number to appear twice in the sequence of sum of cubes of primes dividing n<ref>{{Cite web|url=https://oeis.org/A005064|title=A005064 - OEIS|website=oeis.org}}</ref>
*'''1340''' = k such that 5 × 2<sup>k</sup> - 1 is prime<ref name="auto69">{{cite OEIS|A001770|Numbers k such that 5*2^k - 1 is prime}}</ref>
*'''1341''' = First mountain number with 2 jumps of more than one.
*'''1342''' = <math>\sum_{k=1}^{40} \sigma(k)</math>,<ref name="auto38"/> Mertens function zero
*'''1343''' = [https://oeis.org/A144391/a144391.jpg cropped hexagone]<ref name="auto44">{{cite OEIS|A144391|3*n^2 + n - 1}}</ref>
*'''1344''' = 37<sup>2</sup> - 5<sup>2</sup>, the only way to express 1344 as a difference of prime squares<ref name="auto96">{{cite OEIS|A090781|Numbers that can be expressed as the difference of the squares of primes in just one distinct way}}</ref>
*'''1345''' = k such that k, k+1 and k+2 are products of two primes<ref name="auto81">{{cite OEIS|A056809|Numbers k such that k, k+1 and k+2 are products of two primes}}</ref>
*'''1346''' = number of locally disjointed rooted trees with 10 nodes<ref>{{Cite web|url=https://oeis.org/A316473|title=A316473 - OEIS|website=oeis.org}}</ref>
*'''1347''' = concatenation of first 4 [[Lucas number]]s <ref>{{Cite web|url=https://oeis.org/A000032|title=A000032 - OEIS|website=oeis.org}}</ref>
*'''1348''' = number of ways to stack 22 pennies such that every penny is in a stack of one or two<ref>{{Cite web|url=https://number.academy/1348|title=1348 (number)|website=The encyclopedia of numbers}}</ref>
*'''1349''' = Stern-Jacobsthal number<ref name="auto15">{{cite OEIS|A101624|Stern-Jacobsthal number}}</ref>
*'''1350''' = nonagonal number<ref name="Nonagonal number" />
*'''1351''' = number of partitions of 28 into a prime number of parts<ref name="auto70"/>
*'''1352''' = number of surface points on a cube with edge-length 16,<ref name="A005897" /> [[Achilles number]]
*'''1353''' = 2 × 26<sup>2</sup> + 1 = number of different 2 × 2 determinants with integer entries from 0 to 26<ref name="auto32"/>
*'''1354''' = 2 × 26<sup>2</sup> + 2 = number of points on surface of tetrahedron with edgelength 26<ref name="auto59"/>
*'''1355''' appears for the first time in the [[Recamán's sequence]] at n = 325,374,625,245.<ref>{{cite OEIS|A064228|From Recamán's sequence (A005132): values of n achieving records in A057167}}</ref> Or in other words A057167(1355) = 325,374,625,245<ref>{{cite OEIS|A057167|Term in Recamán's sequence A005132 where n appears for first time, or -1 if n never appears}}</ref><ref>{{cite OEIS|A064227|From Recamán's sequence (A005132): record values in A057167}}</ref>
*'''1356''' is not the sum of a pair of twin primes<ref name="auto99"/>
*'''1357''' = number of nonnegative solutions to x<sup>2</sup> + y<sup>2</sup> ≤ 41<sup>2</sup><ref name="auto65">{{cite OEIS|A000603}}</ref>
*'''1358''' = rounded total surface area of a regular tetrahedron with edge length 28<ref name="auto74"/>
*'''1359''' is the 42d term of Flavius Josephus's sieve<ref>{{cite OEIS|A000960|Flavius Josephus's sieve: Start with the natural numbers; at the k-th sieving step, remove every (k+1)-st term of the sequence remaining after the (k-1)-st sieving step; iterate}}</ref>
*'''1360''' = 37<sup>2</sup> - 3<sup>2</sup>, the only way to express 1360 as a difference of prime squares<ref name="auto96"/>
*'''1361''' = first prime following a [[prime gap]] of 34,<ref name="Prime gap" /> [[centered decagonal number]], 3rd [[Mills' constant|Mills' prime]], Honaker prime<ref name="auto39"/>
*'''1362''' = number of achiral integer partitions of 48<ref name="auto64">{{cite OEIS|A330224|Number of achiral integer partitions of n}}</ref>
*'''1363''' = the number of ways to modify a circular arrangement of 14 objects by swapping one or more adjacent pairs<ref>{{cite OEIS|A001610|a(n-1) + a(n-2) + 1}}</ref>
*'''1364''' = Lucas number<ref>{{cite OEIS|A000032|Lucas numbers: L(n-1) + L(n-2)}}</ref>
*'''1365''' = pentatope number<ref name="Pentatope number">{{Cite web|url=https://oeis.org/A000332|title=Sloane's A000332 : Binomial coefficient binomial(n,4) = n*(n-1)*(n-2)*(n-3)/24|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref>
*'''1366''' = Arima number, after Yoriyuki Arima who in 1769 constructed this sequence as the number of moves of the outer ring in the optimal solution for the Chinese Rings puzzle<ref>{{cite OEIS|A005578|Arima sequence}}</ref>
*'''1367''' = safe prime,<ref name="Safe primes" /> balanced prime, sum of three, nine, and eleven consecutive primes (449 + 457 + 461, 131 + 137 + 139 + 149 + 151 + 157 + 163 + 167 + 173, and 101 + 103 + 107 + 109 + 113 + 127 + 131 + 137 + 139 + 149 + 151),<ref name="Balanced prime" />
*'''1368''' = number of edges in the join of two cycle graphs, both of order 36<ref name="auto89"/>
*'''1369''' = 37<sup>2</sup>, centered octagonal number<ref name="Centered octagonal number" />
*'''1370''' = σ<sub>2</sub>(37): sum of squares of divisors of 37<ref name="auto76">{{cite OEIS|A001157|sigma_2(n): sum of squares of divisors of n}}</ref>
*'''1371''' = sum of the first 28 primes
*'''1372''' = [[Achilles number]]
*'''1373''' = number of lattice points inside a circle of radius 21<ref name="auto22"/>
*'''1374''' = number of unimodular 2 × 2 matrices having all terms in {0,1,...,23}<ref name="auto54"/>
*'''1375''' = decagonal pyramidal number<ref name="auto62"/>
*'''1376''' = primitive abundant number ([[abundant number]] all of whose proper divisors are [[deficient numbers]])<ref name="auto92">{{cite OEIS|A071395|Primitive abundant numbers (abundant numbers all of whose proper divisors are deficient numbers)}}</ref>
*'''1377''' = maximal number of pieces that can be obtained by cutting an annulus with 51 cuts<ref name="auto73"/>
*'''1378''' = 52nd [[triangular number]]<ref name="Triangular number" />
*'''1379''' = [[magic constant]] of ''n'' × ''n'' normal [[magic square]] and [[Eight queens puzzle|''n''-queens problem]] for ''n'' = 14.
*'''1380''' = number of 8-step mappings with 4 inputs<ref name="auto95">{{cite OEIS|A005945|Number of n-step mappings with 4 inputs}}</ref>
*'''1381''' = centered pentagonal number<ref name="Centered pentagonal" /> Mertens function zero
*'''1382''' = first 4 digit tetrachi number <ref>{{Cite web|url=https://oeis.org/A001631|title=A001631 - OEIS|website=oeis.org|accessdate=25 June 2023}}</ref>
*'''1383''' = 3 × 461. 10<sup>1383</sup> + 7 is prime<ref>{{cite OEIS|A088274|Numbers k such that 10^k + 7 is prime}}</ref>
*'''1384''' = <math>\sum_{k=1}^{41} \sigma(k)</math><ref name="auto38"/>
*'''1385''' = up/down number<ref>{{cite OEIS|A000111|Euler or up/down numbers: e.g.f. sec(x) + tan(x)}}</ref>
*'''1386''' = octagonal pyramidal number<ref>{{cite OEIS|A002414|Octagonal pyramidal numbers}}</ref>
*'''1387''' = 5th [[Fermat pseudoprime]] of base 2,<ref>{{Cite web|url=https://oeis.org/A001567|title=Sloane's A001567 : Fermat pseudoprimes to base 2|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> 22nd [[centered hexagonal number]] and the 19th [[decagonal number]],<ref name="Decagonal" /> second [[Super-Poulet number]].<ref>{{Cite web|url=https://oeis.org/A050217|title=Sloane's A050217 : Super-Poulet numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref>
*'''1388''' = 4 × 19<sup>2</sup> - 3 × 19 + 1 and is therefore on the x-axis of [[Ulams spiral]]<ref>{{cite OEIS|A054552|4*n^2 - 3*n + 1}}</ref>
*'''1389''' = sum of first 42 composite numbers<ref name="auto94"/>
*'''1390''' = sum of first 43 nonprimes<ref name="ReferenceB"/>
*'''1391''' = number of rational numbers which can be constructed from the set of integers between 1 and 47<ref name="auto56"/>
*'''1392''' = number of edges in the [[:File:Hexagonal triangle.png|hexagonal triangle]] T(29)<ref name="auto60"/>
*'''1393''' = 7-Knödel number<ref name="auto21"/>
*'''1394''' = sum of totient function for first 67 integers
*'''1395''' = [[vampire number]],<ref name="Vampire number" /> member of the Mian–Chowla sequence<ref name=Mian-Chowla /> triangular matchstick number<ref name="auto5"/>
*'''1396''' = [[centered triangular number]]<ref name="auto52"/>
*'''1397''' = <math>\left \lfloor 5^{\frac{9}{2}} \right \rfloor</math><ref>{{cite OEIS|A017919|Powers of sqrt(5) rounded down}}</ref>
*'''1398''' = number of integer partitions of 40 whose distinct parts are connected<ref name="auto86"/>
*'''1399''' = emirp<ref>{{cite OEIS|A109308|Lesser emirps (primes whose digit reversal is a larger prime)}}</ref>

=== 1400 to 1499 ===
*'''1400''' = number of sum-free subsets of {1, ..., 15}<ref name="auto41">{{cite OEIS|A007865|Number of sum-free subsets of {1, ..., n}<nowiki />}}</ref>
*'''1401''' = pinwheel number<ref name="Pinwheel" />
*'''1402''' = number of integer partitions of 48 whose augmented differences are distinct,<ref name="auto19">{{cite OEIS|A325349|Number of integer partitions of n whose augmented differences are distinct}}</ref> number of signed trees with 8 nodes<ref>{{cite OEIS|A000060|Number of signed trees with n nodes}}</ref>
*'''1403''' = smallest x such that M(x) = 11, where M() is [[Mertens function]]<ref name="ReferenceC">{{cite OEIS|A051400|Smallest value of x such that M(x) equals n, where M() is Mertens's function A002321}}</ref>
*'''1404''' = heptagonal number<ref name="heptagonal number" />
*'''1405''' = 26<sup>2</sup> + 27<sup>2</sup>, 7<sup>2</sup> + 8<sup>2</sup> + ... + 16<sup>2</sup>, centered square number<ref name="Centered square numbers" />
*'''1406''' = pronic number,<ref name="pronic number" /> [[semi-meandric number]]<ref>{{Cite web|url=https://oeis.org/A000682|title=Sloane's A000682 : Semimeanders|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref>
*'''1407''' = 38<sup>2</sup> - 38 + 1 = H<sub>38</sub> (the 38th Hogben number)<ref name="auto77"/>
*'''1408''' = maximal number of regions the plane is divided into by drawing 38 circles<ref name="auto27"/>
*'''1409''' = [[super-prime]], Sophie Germain prime,<ref name="Sophie Germain" /> smallest number whose eighth power is the sum of 8 eighth powers, Proth prime<ref name="Proth prime" />
*'''1410''' = denominator of the 46th [[Bernoulli number]]<ref>{{cite OEIS|A002445|Denominators of Bernoulli numbers B_{2n}<nowiki />}}</ref>
*'''1411''' = LS(41)<ref name="ReferenceD">{{cite OEIS|A045918|Describe n. Also called the "Say What You See" or "Look and Say" sequence LS(n)}}</ref>
*'''1412''' = LS(42),<ref name="ReferenceD"/> spy number
*'''1413''' = LS(43)<ref name="ReferenceD"/>
*'''1414''' = smallest composite that when added to sum of prime factors reaches a prime after 27 iterations<ref name="auto37">{{cite OEIS|A050710|Smallest composite that when added to sum of prime factors reaches a prime after n iterations}}</ref>
*'''1415''' = the Mahonian number: T(8, 8)<ref name="A008302" />
*'''1416''' = LS(46)<ref name="ReferenceD"/>
*'''1417''' = number of partitions of 32 in which the number of parts divides 32<ref name="auto63">{{cite OEIS|A067538|Number of partitions of n in which the number of parts divides n}}</ref>
*'''1418''' = smallest x such that M(x) = 13, where M() is [[Mertens function]]<ref name="ReferenceC"/>
*'''1419''' = Zeisel number<ref name="Zeisel number">{{Cite web|url=https://oeis.org/A051015|title=Sloane's A051015 : Zeisel numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref>
*'''1420''' = [[oeis:A000607|Number of partitions of 56 into prime parts]]
*'''1421''' = maximum dimension of Euclidean spaces which suffice for every smooth compact Riemannian 29-manifold to be realizable as a sub-manifold,<ref name="ReferenceE">{{cite OEIS|A059845|n*(3*n + 11)/2}}</ref> spy number
*'''1422''' = number of partitions of 15 with two parts marked<ref>{{cite OEIS|A000097|Number of partitions of n if there are two kinds of 1's and two kinds of 2's}}</ref>
*'''1423''' = 200 + 1223 and the 200th prime is 1223<ref name="auto47">{{cite OEIS|A061068|Primes which are the sum of a prime and its subscript}}</ref> Also Used as a Hate symbol
*'''1424''' = number of nonnegative solutions to x<sup>2</sup> + y<sup>2</sup> ≤ 42<sup>2</sup><ref name="auto65"/>
*'''1425''' = [[self-descriptive number]] in base 5
*'''1426''' = sum of totient function for first 68 integers, pentagonal number,<ref name="Pentagonal number" /> number of strict partions of 42<ref name="auto20"/>
*'''1427''' = [[twin prime]] together with 1429<ref>{{cite OEIS|A001359|Lesser of twin primes}}</ref>
*'''1428''' = number of complete ternary trees with 6 internal nodes, or 18 edges<ref>{{cite OEIS|A001764|binomial(3*n,n)/(2*n+1) (enumerates ternary trees and also noncrossing trees)}}</ref>
*'''1429''' = number of partitions of 53 such that the smallest part is greater than or equal to number of parts<ref name="auto75"/>
*'''1430''' = [[Catalan number]]<ref>{{Cite web|url=https://oeis.org/A000108|title=Sloane's A000108 : Catalan numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref>
*'''1431''' = 53rd [[triangular number]],<ref name="Triangular number" /> hexagonal number<ref name="Hexagonal number" />
*'''1432''' = member of Padovan sequence<ref name="Padovan sequence" />
*'''1433''' = [[super-prime]], Honaker prime,<ref name="auto39"/> typical port used for remote connections to [[Microsoft SQL Server]] [[database]]s
*'''1434''' = rounded volume of a regular tetrahedron with edge length 23<ref name="auto88">{{cite OEIS|A071399|Rounded volume of a regular tetrahedron with edge length n}}</ref>
*'''1435''' = [[vampire number]];<ref name="Vampire number" /> the standard railway gauge in millimetres, equivalent to {{convert|4|ft|8+1/2|in}}
*'''1436''' = discriminant of a totally real cubic field<ref name="ReferenceF">{{cite OEIS|A006832|Discriminants of totally real cubic fields}}</ref>
*'''1437''' = smallest number of complexity 20: smallest number requiring 20 1's to build using +, * and ^<ref name="auto49">{{cite OEIS|A003037|Smallest number of complexity n: smallest number requiring n 1's to build using +, * and ^}}</ref>
*'''1438''' = k such that 5 × 2<sup>k</sup> - 1 is prime<ref name="auto69"/>
*'''1439''' = Sophie Germain prime,<ref name="Sophie Germain" /> safe prime<ref name="Safe primes" />
*'''1440''' = a [[highly totient number]],<ref name="highly totient" /> a largely composite number<ref name="OEIS-A067128"/> and a 481-[[polygonal number|gonal number]]. Also, the number of [[minute]]s in one day, the blocksize of a standard {{sfrac|3|1|2}} [[floppy disk]], and the horizontal resolution of [[WSXGA Wide XGA+|WXGA(II)]] computer displays
*'''1441''' = star number<ref name="Centered 12-gonal numbers" />
*'''1442''' = number of parts in all partitions of 31 into distinct parts<ref name="auto46"/>
*'''1443''' = the sum of the second trio of three-digit [[permutable prime]]s in [[decimal]]: [[337 (number)|337]], [[373 (number)|373]], and [[733 (number)|733]]. Also the number of edges in the join of two cycle graphs, both of order [[37 (number)|37]]<ref name="auto89"/>
*'''1444''' = 38<sup>2</sup>, smallest [[pandigital number]] in [[Roman numerals]]
*'''1445''' = <math>\sum_{k=0}^3 \left( \binom{3}{k} \times \binom{3+k}{k} \right) ^2</math><ref>{{cite OEIS|A005259|Apery (Apéry) numbers: Sum_0^n (binomial(n,k)*binomial(n+k,k))^2}}</ref>
*'''1446''' = number of points on surface of octahedron with edge length 19<ref name="auto61"/>
*'''1447''' = [[super-prime]], [[happy number]]
*'''1448''' = number k such that phi(prime(k)) is a square<ref name="auto55">{{cite OEIS|A062325|Numbers k for which phi(prime(k)) is a square}}</ref>
*'''1449''' = [[Stella octangula number]]
*'''1450''' = σ<sub>2</sub>(34): sum of squares of divisors of 34<ref name="auto76"/>
*'''1451''' = Sophie Germain prime<ref name="Sophie Germain" />
*'''1452''' = first Zagreb index of the complete graph K<sub>12</sub><ref name="auto100">{{cite OEIS|A011379|n^2*(n+1)}}</ref>
*'''1453''' = [[Sexy prime]] with 1459
*'''1454''' = 3 × 22<sup>2</sup> + 2 = number of points on surface of square pyramid of side-length 22<ref name="auto58">{{cite OEIS|A005918|Number of points on surface of square pyramid: 3*n^2 + 2 (n>0)}}</ref>
*'''1455''' = k such that geometric mean of phi(k) and sigma(k) is an integer<ref name="auto68">{{cite OEIS|A011257|Geometric mean of phi(n) and sigma(n) is an integer}}</ref>
*'''1456''' = number of regions in regular 15-gon with all diagonals drawn<ref>{{cite OEIS|A007678|Number of regions in regular n-gon with all diagonals drawn}}</ref>
*'''1457''' = 2 × 27<sup>2</sup> − 1 = a [https://oeis.org/A056220/a056220.jpg twin square]<ref name="auto83">{{cite OEIS|A056220|2*n^2 - 1}}</ref>
*'''[[1458 (number)|1458]]''' = [[Hadamard's maximal determinant problem|maximum determinant]] of an 11 by 11 matrix of zeroes and ones, [[3-smooth]] number (2×3<sup>6</sup>)
*'''1459''' = Sexy prime with 1453, sum of nine consecutive primes (139 + 149 + 151 + 157 + 163 + 167 + 173 + 179 + 181), [[Pierpont prime]]
*'''1460''' = The number of years that would have to pass in the [[Julian calendar]] in order to accrue a full year's worth of leap days.
*'''1461''' = number of partitions of 38 into prime power parts<ref name="auto87"/>
*'''1462''' = (35 - 1) × (35 + 8) = the first Zagreb index of the wheel graph with 35 vertices<ref>{{cite OEIS|A028569|n*(n + 9)}}</ref>
*'''1463''' = total number of parts in all partitions of 16<ref name="auto16"/>
*'''1464''' = rounded total surface area of a regular icosahedron with edge length 13<ref>{{cite OEIS|A071398|Rounded total surface area of a regular icosahedron with edge length n}}</ref>
*'''1465''' = 5-[[Knödel number]]<ref name="auto14"/>
*'''1466''' = <math>\sum_{k=1}^{256} d(k)</math>, where <math>d(k)</math> = number of divisors of <math>k</math><ref>{{cite OEIS|A085831|Sum_1^{2^n} d(k) where d(k) is the number of divisors of k (A000005)}}</ref>
*'''1467''' = number of partitions of 39 with zero crank<ref>{{cite OEIS|A064410|Number of partitions of n with zero crank}}</ref>
*'''1468''' = number of polyhexes with 11 cells that tile the plane by translation<ref>{{cite OEIS|A075207|Number of polyhexes with n cells that tile the plane by translation}}</ref>
*'''1469''' = octahedral number,<ref name="Octahedral number" /> highly cototient number<ref name="highly cototient" />
*'''1470''' = [[pentagonal pyramidal number]],<ref name="Pentagonal pyramidal number">{{Cite web|url=https://oeis.org/A002411|title=Sloane's A002411 : Pentagonal pyramidal numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> sum of totient function for first 69 integers
*'''1471''' = [[super-prime]], centered heptagonal number<ref name="centered heptagonal number" />
*'''1472''' = number of overpartitions of 15<ref>{{cite OEIS|A015128|Number of overpartitions of n: an overpartition of n is an ordered sequence of nonincreasing integers that sum to n, where the first occurrence of each integer may be overlined}}</ref>
*'''1473''' = [https://oeis.org/A144391/a144391.jpg cropped hexagone]<ref name="auto44"/>
*'''1474''' = <math>\frac{44(44 + 1)}{2} + \frac{44^2}{4}</math>: triangular number plus quarter square (i.e., A000217(44) + A002620(44))<ref>{{cite OEIS|A006578|Triangular numbers plus quarter squares: n*(n+1)/2 + floor(n^2/4) (i.e., A000217(n) + A002620(n))}}</ref>
*'''1475''' = number of partitions of 33 into parts each of which is used a different number of times<ref name="ReferenceG">{{cite OEIS|A098859|Number of partitions of n into parts each of which is used a different number of times}}</ref>
*'''1476''' = coreful perfect number<ref name="auto31">{{cite OEIS|A307958|Coreful perfect numbers}}</ref>
*'''1477''' = 7-Knödel number<ref name="auto21"/>
*'''1478''' = total number of largest parts in all compositions of 11<ref>{{cite OEIS|A097979|Total number of largest parts in all compositions of n}}</ref>
*'''1479''' = number of planar partitions of 12<ref>{{cite OEIS|A000219|Number of planar partitions (or plane partitions) of n}}</ref>
*'''1480''' = sum of the first 29 primes
*'''1481''' = Sophie Germain prime<ref name="Sophie Germain" />
*'''1482''' = pronic number,<ref name="pronic number" /> number of unimodal compositions of 15 where the maximal part appears once<ref>{{cite OEIS|A006330|Number of corners, or planar partitions of n with only one row and one column}}</ref>
*'''1483''' = 39<sup>2</sup> - 39 + 1 = H<sub>39</sub> (the 39th Hogben number)<ref name="auto77"/>
*'''1484''' = maximal number of regions the plane is divided into by drawing 39 circles<ref name="auto27"/>
*'''1485''' = 54th [[triangular number]]<ref name="Triangular number" />
*'''1486''' = number of strict solid partitions of 19<ref name="auto43"/>
*'''1487''' = safe prime<ref name="Safe primes" />
*'''1488''' = triangular matchstick number<ref name="auto5"/>
*'''1489''' = [[centered triangular number]]<ref name="auto52"/>
*'''1490''' = [[tetranacci number]]<ref>{{Cite web|url=https://oeis.org/A000078|title=Sloane's A000078 : Tetranacci numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref>
*'''1491''' = nonagonal number,<ref name="Nonagonal number" /> Mertens function zero
*'''1492''' = discriminant of a totally real cubic field,<ref name="ReferenceF"/> Mertens function zero
*'''1493''' = Stern prime<ref name="Stern prime" />
*'''1494''' = sum of totient function for first 70 integers
*'''1495''' = 9###<ref>{{cite OEIS|A114411|Triple primorial n###}}</ref>
*'''1496''' = square pyramidal number<ref name="Square pyramidal numbers" />
*'''1497''' = skiponacci number<ref name="auto25"/>
*'''1498''' = number of flat partitions of 41<ref name="auto26">{{cite OEIS|A034296|Number of flat partitions of n}}</ref>
*'''1499''' = Sophie Germain prime,<ref name="Sophie Germain" /> [[super-prime]]

=== 1500 to 1599 ===

*'''1500''' = hypotenuse in three different Pythagorean triangles<ref name="auto101">{{cite OEIS|A084647|Hypotenuses for which there exist exactly 3 distinct integer triangles}}</ref>
*'''1501''' = centered pentagonal number<ref name="Centered pentagonal" />
*'''1502''' = number of pairs of consecutive integers x, x+1 such that all prime factors of both x and x+1 are at most 47<ref name="auto80">{{cite OEIS|A002071|Number of pairs of consecutive integers x, x+1 such that all prime factors of both x and x+1 are at most the n-th prime}}</ref>
*'''1503''' = least number of triangles of the [[Spiral of Theodorus]] to complete 12 revolutions<ref name="auto85"/>
*'''1504''' = primitive abundant number ([[abundant number]] all of whose proper divisors are [[deficient numbers]])<ref name="auto92"/>
*'''1505''' = number of integer partitions of 41 with distinct differences between successive parts<ref>{{cite OEIS|A325325|Number of integer partitions of n with distinct differences between successive parts}}</ref>
*'''1506''' = number of Golomb partitions of 28<ref>{{cite OEIS|A325858|Number of Golomb partitions of n}}</ref>
*'''1507''' = number of partitions of 32 that do not contain 1 as a part<ref name="auto8"/>
*'''1508''' = heptagonal pyramidal number<ref name="auto82"/>
*'''1509''' = pinwheel number<ref name="Pinwheel" />
*'''[[1510 (number)|1510]]''' = [[deficient number]], [[odious number]]
*'''1511''' = Sophie Germain prime,<ref name="Sophie Germain" /> balanced prime<ref name="Balanced prime" />
*'''1512''' = k such that geometric mean of phi(k) and sigma(k) is an integer<ref name="auto68"/>
*'''1513''' = centered square number<ref name="Centered square numbers" />
*'''1514''' = sum of first 44 composite numbers<ref name="auto94"/>
*'''1515''' = maximum dimension of Euclidean spaces which suffice for every smooth compact Riemannian 30-manifold to be realizable as a sub-manifold<ref name="ReferenceE"/>
*'''1516''' = <math>\left \lfloor 9^\frac{10}{3} \right \rfloor </math><ref>{{cite OEIS|A018000|Powers of cube root of 9 rounded down}}</ref>
*'''1517''' = number of lattice points inside a circle of radius 22<ref name="auto22"/>
*'''1518''' = sum of first 32 semiprimes,<ref>{{cite OEIS|A062198|Sum of first n semiprimes}}</ref> Mertens function zero
*'''1519''' = number of polyhexes with 8 cells,<ref>{{cite OEIS|A038147|Number of polyhexes with n cells}}</ref> Mertens function zero
*'''1520''' = pentagonal number,<ref name="Pentagonal number" /> Mertens function zero, forms a Ruth–Aaron pair with 1521 under second definition
*'''1521''' = 39<sup>2</sup>, Mertens function zero, centered octagonal number,<ref name="Centered octagonal number" /> forms a Ruth–Aaron pair with 1520 under second definition
*'''1522''' = k such that 5 × 2<sup>k</sup> - 1 is prime<ref name="auto69"/>
*'''1523''' = [[super-prime]], Mertens function zero, safe prime,<ref name="Safe primes" /> member of the Mian–Chowla sequence<ref name=Mian-Chowla />
*'''1524''' = Mertens function zero, k such that geometric mean of phi(k) and sigma(k) is an integer<ref name="auto68"/>
*'''1525''' = heptagonal number,<ref name="heptagonal number" /> Mertens function zero
*'''1526''' = number of conjugacy classes in the alternating group A<sub>27</sub><ref name="auto33">{{cite OEIS|A000702|number of conjugacy classes in the alternating group A_n}}</ref>
*'''1527''' = number of 2-dimensional partitions of 11,<ref>{{cite OEIS|A001970|Functional determinants; partitions of partitions; Euler transform applied twice to all 1's sequence}}</ref> Mertens function zero
*'''1528''' = Mertens function zero, rounded total surface area of a regular octahedron with edge length 21<ref>{{cite OEIS|A071396|Rounded total surface area of a regular octahedron with edge length n}}</ref>
*'''1529''' = composite [[de Polignac number]]<ref name="auto53"/>
*'''1530''' = [[vampire number]]<ref name="Vampire number" />
*'''1531''' = prime number, [[centered decagonal number]], Mertens function zero
*'''1532''' = number of series-parallel networks with 9 unlabeled edges,<ref>{{cite OEIS|A000084|Number of series-parallel networks with n unlabeled edges. Also called yoke-chains by Cayley and MacMahon}}</ref> Mertens function zero
*'''1533''' = 21 × 73 = 21 × 21st prime<ref name="cite OEIS|A033286|n * primen"/>
*'''1534''' = number of achiral integer partitions of 50<ref name="auto64"/>
*'''1535''' = [[Thabit number]]
*'''1536''' = a common size of [[microplate]], [[3-smooth]] number (2<sup>9</sup>×3), number of threshold functions of exactly 4 variables<ref>{{cite OEIS|A000615|Threshold functions of exactly n variables}}</ref>
*'''1537''' = Keith number,<ref name="Keith number" /> Mertens function zero
*'''1538''' = number of surface points on a cube with edge-length 17<ref name="A005897">{{cite OEIS|A005897|6*n^2 + 2 for n > 0}}</ref>
*'''1539''' = maximal number of pieces that can be obtained by cutting an annulus with 54 cuts<ref name="auto73"/>
*'''1540''' = 55th [[triangular number]],<ref name="Triangular number" /> hexagonal number,<ref name="Hexagonal number" /> decagonal number,<ref name="Decagonal" /> tetrahedral number<ref name="Tetrahedral nu"/>
*'''1541''' = [[octagonal number]]<ref name="auto17"/>
*'''1542''' = k such that 2^k starts with k<ref>{{cite OEIS|A100129|Numbers k such that 2^k starts with k}}</ref>
*'''1543''' = prime dividing all Fibonacci sequences,<ref>{{cite OEIS|A000057|Primes dividing all Fibonacci sequences}}</ref> Mertens function zero
*'''1544''' = Mertens function zero, number of partitions of integer partitions of 17 where all parts have the same length<ref>{{cite OEIS|A319066|Number of partitions of integer partitions of n where all parts have the same length}}</ref>
*'''1545''' = number of reversible string structures with 9 beads using exactly three different colors<ref>{{cite OEIS|A056327|Number of reversible string structures with n beads using exactly three different colors}}</ref>
*'''1546''' = number of 5 X 5 binary matrices with at most one 1 in each row and column,<ref>{{cite OEIS|A002720|Number of partial permutations of an n-set; number of n X n binary matrices with at most one 1 in each row and column}}</ref> Mertens function zero
*'''1547''' = [[hexagonal pyramidal number]]
*'''1548''' = coreful perfect number<ref name="auto31"/>
*'''1549''' = [[de Polignac number|de Polignac]] prime<ref name="auto67">{{cite OEIS|A065381|Primes not of the form p + 2^k}}</ref>
*'''1550''' = <math>\frac {31 \times (3 \times 31 + 7)}{2}</math> = number of cards needed to build a 31-tier house of cards with a flat, one-card-wide roof<ref>{{cite OEIS|A140090|n*(3*n + 7)/2}}</ref>
*'''1551''' = 6920 - 5369 = A169952(24) - A169952(23) = A169942(24) = number of Golomb rulers of length 24<ref>{{cite OEIS|A169942|Number of Golomb rulers of length n}}</ref><ref>{{cite OEIS|A169952|Second entry in row n of triangle in A169950}}</ref>
*'''1552''' = [[oeis:A000607|Number of partitions of 57 into prime parts]]
*'''1553''' = 509 + 521 + 523 = a prime that is the sum of three consecutive primes<ref>{{cite OEIS|A034962|Primes that are the sum of three consecutive primes}}</ref>
*'''1554''' = 2 × 3 × 7 × 37 = product of four distinct primes<ref>{{cite OEIS|A046386|Products of four distinct primes}}</ref>
*'''1555'''<sup>2</sup> divides 6<sup>1554</sup><ref>{{cite OEIS|A127106|Numbers n such that n^2 divides 6^n-1}}</ref>
*'''1556''' = sum of the squares of the first nine primes
*'''1557''' = number of graphs with 8 nodes and 13 edges<ref name="auto78">{{cite OEIS|A008406|Triangle T(n,k) read by rows, giving number of graphs with n nodes and k edges)}}</ref>
*'''1558''' = [[oeis:A006316|number k]] such that k<sup>64</sup> + 1 is prime
*'''1559''' = Sophie Germain prime<ref name="Sophie Germain" />
*'''1560''' = pronic number<ref name="pronic number" />
*'''1561''' = a [[centered octahedral number]],<ref name="auto7"/> number of series-reduced trees with 19 nodes<ref>{{cite OEIS|A000014|Number of series-reduced trees with n nodes}}</ref>
*'''1562''' = maximal number of regions the plane is divided into by drawing 40 circles<ref name="auto27"/>
*'''1563''' = <math>\sum_{k=1}^{50} \frac{50}{\gcd(50,k)}</math><ref>{{cite OEIS|A057660|Sum_{1..n} n/gcd(n,k)}}</ref>
*'''1564''' = sum of totient function for first 71 integers
*'''1565''' = <math>\sqrt{1036^2+1173^2}</math> and <math>1036+1173=47^2</math><ref>{{cite OEIS|A088319|Ordered hypotenuses of primitive Pythagorean triangles having legs that add up to a square}}</ref>
*'''1566''' = [[oeis:A006316|number k]] such that k<sup>64</sup> + 1 is prime
*'''1567''' = number of partitions of 24 with at least one distinct part<ref name="auto66"/>
*'''1568''' = [[Achilles number]]<ref name="Achilles">{{cite OEIS|A052486|Achilles numbers}}</ref>
*'''1569''' = 2 × 28<sup>2</sup> + 1 = number of different 2 × 2 determinants with integer entries from 0 to 28<ref name="auto32"/>
*'''1570''' = 2 × 28<sup>2</sup> + 2 = number of points on surface of tetrahedron with edgelength 28<ref name="auto59"/>
*'''1571''' = Honaker prime<ref name="auto39"/>
*'''1572''' = member of the Mian–Chowla sequence<ref name=Mian-Chowla />
*'''1573''' = discriminant of a totally real cubic field<ref name="ReferenceF"/>
*'''1574'''<sup>256</sup> + 1 is prime<ref>{{cite OEIS|A056995|Numbers k such that k^256 + 1 is prime}}</ref>
*'''1575''' = odd [[abundant number]],<ref>{{Cite web|url=https://oeis.org/A005231|title=Sloane's A005231 : Odd abundant numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> [[oeis:A006002|sum of the nontriangular numbers between successive triangular numbers]], number of partitions of 24<ref name="auto35"/>
*'''1576'''<sup>14</sup> == 1 (mod 15^2)<ref>{{cite OEIS|A056026|Numbers k such that k^14 is congruent with 1 (mod 15^2)}}</ref>
*'''1577''' = sum of the quadratic residues of 83<ref>{{cite OEIS|A076409|Sum of the quadratic residues of prime(n)}}</ref>
*'''1578''' = sum of first 45 composite numbers<ref name="auto94"/>
*'''1579''' = number of partitions of 54 such that the smallest part is greater than or equal to number of parts<ref name="auto75"/>
*'''1580''' = number of achiral integer partitions of 51<ref name="auto64"/>
*'''1581''' = number of edges in the [[:File:Hexagonal triangle.png|hexagonal triangle]] T(31)<ref name="auto60"/>
*'''1582''' = a number such that the integer triangle [A070080(1582), A070081(1582), A070082(1582)] has an integer area<ref>{{cite OEIS|A070142|Numbers n such that [A070080(n), A070081(n), A070082(n)] is an integer triangle with integer area}}</ref>
*'''1583''' = Sophie Germain prime
*'''1584''' = triangular matchstick number<ref name="auto5"/>
*'''1585''' = [[oeis:A005043|Riordan number]], [[centered triangular number]]<ref name="auto52"/>
*'''1586''' = area of the 23rd [https://oeis.org/A080663/a080663.jpg conjoined trapezoid]<ref name="auto13"/>
*'''1587''' = 3 × 23<sup>2</sup> = number of edges of a complete tripartite graph of order 69, K<sub>23,23,23</sub><ref>{{cite OEIS|A033428|3*n^2}}</ref>
*'''1588''' = sum of totient function for first 72 integers
*'''1589''' = composite [[de Polignac number]]<ref name="auto53"/>
*'''1590''' = rounded volume of a regular icosahedron with edge length 9<ref>{{cite OEIS|A071402|Rounded volume of a regular icosahedron with edge length n}}</ref>
*'''1591''' = rounded volume of a regular octahedron with edge length 15<ref name="auto84"/>
*'''1592''' = sum of all divisors of the first 36 odd numbers<ref>{{cite OEIS|A326123|a(n) is the sum of all divisors of the first n odd numbers}}</ref>
*'''1593''' = sum of the first 30 primes
*'''1594''' = minimal cost of maximum height Huffman tree of size 17<ref>{{cite OEIS|A006327|Fibonacci(n) - 3. Number of total preorders}}</ref>
*'''1595''' = [[oeis:A283877|number of non-isomorphic set-systems of weight 10]]
*'''1596''' = 56th [[triangular number]]<ref name="Triangular number" />
*'''1597''' = [[Fibonacci prime]],<ref>{{Cite web|url=https://oeis.org/A000045|title=Sloane's A000045 : Fibonacci numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> [[Markov prime]],<ref name="Markov number" /> [[super-prime]], [[emirp]]
*'''1598''' = number of unimodular 2 × 2 matrices having all terms in {0,1,...,25}<ref name="auto54"/>
*'''1599''' = number of edges in the join of two cycle graphs, both of order 39<ref name="auto89"/>

=== 1600 to 1699 ===

*'''1600''' = 40<sup>2</sup>, structured great rhombicosidodecahedral number,<ref>{{cite OEIS|A100145|Structured great rhombicosidodecahedral numbers}}</ref> repdigit in base 7 (4444<sub>7</sub>), street number on Pennsylvania Avenue of the [[White House]], length in meters of a common High School Track Event, perfect score on [[SAT]] (except from 2005 to 2015)
*'''1601''' = Sophie Germain prime, Proth prime,<ref name="Proth prime" /> the novel ''[[1601 (Mark Twain)]]''
*'''1602''' = number of points on surface of octahedron with edgelength 20<ref name="auto61"/>
*'''1603''' = number of partitions of 27 with nonnegative rank<ref name="auto18">{{cite OEIS|A064174|Number of partitions of n with nonnegative rank}}</ref>
*'''1604''' = number of compositions of 22 into prime parts<ref>{{cite OEIS|A023360|Number of compositions of n into prime parts}}</ref>
*'''1605''' = number of polyominoes consisting of 7 regular octagons<ref>{{cite OEIS|A103473|Number of polyominoes consisting of 7 regular unit n-gons}}</ref>
*'''1606''' = enneagonal pyramidal number<ref>{{cite OEIS|A007584|9-gonal (or enneagonal) pyramidal numbers}}</ref>
*'''1607''' = member of prime triple with 1609 and 1613<ref>{{cite OEIS|A022004|Initial members of prime triples (p, p+2, p+6)}}</ref>
*'''1608''' = <math>\sum_{k=1}^{44} \sigma(k)</math><ref name="auto38"/>
*'''1609''' = [https://oeis.org/A144391/a144391.jpg cropped hexagonal number]<ref name="auto44"/>
*'''1610''' = number of strict partions of 43<ref name="auto20"/>
*'''1611''' = number of rational numbers which can be constructed from the set of integers between 1 and 51<ref name="auto56"/>
*'''1612''' = maximum dimension of Euclidean spaces which suffice for every smooth compact Riemannian 31-manifold to be realizable as a sub-manifold<ref name="ReferenceE"/>
*'''1613''', 1607 and 1619 are all primes<ref>{{cite OEIS|A006489|Numbers k such that k-6, k, and k+6 are primes}}</ref>
*'''1614''' = number of ways of refining the partition 8^1 to get 1^8<ref>{{cite OEIS|A213427|Number of ways of refining the partition n^1 to get 1^n}}</ref>
*'''1615''' = composite number such that the square mean of its prime factors is a nonprime integer<ref>{{cite OEIS|A134602|Composite numbers such that the square mean of their prime factors is a nonprime integer (where the prime factors are taken with multiplicity and the square mean of c and d is sqrt((c^2+d^2)/2))}}</ref>
*'''1616''' = <math>\frac{16(16^2 + 3 \times 16 - 1)}{3}</math> = number of monotonic triples (x,y,z) in {1,2,...,16}<sup>3</sup><ref>{{cite OEIS|A084990|n*(n^2+3*n-1)/3}}</ref>
*'''1617''' = pentagonal number<ref name="Pentagonal number" />
*'''1618''' = centered heptagonal number<ref name="centered heptagonal number" />
*'''1619''' = [[palindromic prime]] in [[Binary numeral system|binary]], safe prime<ref name="Safe primes" />
*'''1620''' = 809 + 811: sum of twin prime pair<ref name="auto48"/>
*'''1621''' = [[super-prime]], pinwheel number<ref name="Pinwheel" />
*'''1622''' = semiprime of the form prime + 1<ref>{{cite OEIS|A077068|Semiprimes of the form prime + 1}}</ref>
*'''1623''' is not the sum of two triangular numbers and a fourth power<ref>{{cite OEIS|A115160|Numbers that are not the sum of two triangular numbers and a fourth power}}</ref>
*'''1624''' = number of squares in the [[Aztec diamond]] of order 28<ref name="auto36">{{cite OEIS|A046092|4 times triangular numbers}}</ref>
*'''1625''' = centered square number<ref name="Centered square numbers" />
*'''1626''' = centered pentagonal number<ref name="Centered pentagonal" />
*'''1627''' = prime and 2 × 1627 - 1 = 3253 is also prime<ref>{{cite OEIS|A005382|Primes p such that 2p-1 is also prime}}</ref>
*'''1628''' = centered pentagonal number<ref name="Centered pentagonal" />
*'''1629''' = rounded volume of a regular tetrahedron with edge length 24<ref name="auto88"/>
*'''1630''' = [[oeis:A006316|number k such that k^64 + 1 is prime]]
*'''1631''' = <math>\sum_{k=0}^{5} (k+1)! \binom{5}{k}</math><ref>{{cite OEIS|A001339|Sum_{0..n} (k+1)! binomial(n,k)}}</ref>
*'''1632''' = number of acute triangles made from the vertices of a regular 18-polygon<ref>{{cite OEIS|A007290|2*binomial(n,3)}}</ref>
*'''1633''' = star number<ref name="Centered 12-gonal numbers" />
*'''1634''' = [[Narcissistic number]] in base 10
*'''1635''' = number of partitions of 56 whose reciprocal sum is an integer<ref>{{cite OEIS|A058360|Number of partitions of n whose reciprocal sum is an integer}}</ref>
*'''1636''' = number of nonnegative solutions to x<sup>2</sup> + y<sup>2</sup> ≤ 45<sup>2</sup><ref name="auto65"/>
*'''1637''' = prime island: least prime whose adjacent primes are exactly 30 apart<ref>{{cite OEIS|A046931|Prime islands: least prime whose adjacent primes are exactly 2n apart}}</ref>
*'''1638''' = [[harmonic divisor number]],<ref>{{Cite web|url=https://oeis.org/A001599|title=Sloane's A001599 : Harmonic or Ore numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> 5 × 2<sup>1638</sup> - 1 is prime<ref name="auto69"/>
*'''1639''' = nonagonal number<ref name="Nonagonal number" />
*'''1640''' = pronic number<ref name="pronic number" />
*'''1641''' = 41<sup>2</sup> - 41 + 1 = H<sub>41</sub> (the 41st Hogben number)<ref name="auto77"/>
*'''1642''' = maximal number of regions the plane is divided into by drawing 41 circles<ref name="auto27"/>
*'''1643''' = sum of first 46 composite numbers<ref name="auto94"/>
*'''1644''' = 821 + 823: sum of twin prime pair<ref name="auto48"/>
*'''1645''' = number of 16-celled pseudo still lifes in Conway's Game of Life, up to rotation and reflection<ref>{{cite OEIS|A056613|Number of n-celled pseudo still lifes in Conway's Game of Life, up to rotation and reflection}}</ref>
*'''1646''' = number of graphs with 8 nodes and 14 edges<ref name="auto78"/>
*'''1647''' and 1648 are both divisible by cubes<ref>{{cite OEIS|A068140|Smaller of two consecutive numbers each divisible by a cube greater than one}}</ref>
*'''1648''' = number of partitions of 34<sup>3</sup> into distinct cubes<ref>{{cite OEIS|A030272|Number of partitions of n^3 into distinct cubes}}</ref>
*'''1649''' = highly cototient number,<ref name="highly cototient" /> [[Leyland number]]<ref name=A076980/> using 4 & 5 (4<sup>5</sup> + 5<sup>4</sup>)
*'''1650''' = number of cards to build an 33-tier house of cards<ref name="auto45"/>
*'''1651''' = heptagonal number<ref name="heptagonal number" />
*'''1652''' = number of partitions of 29 into a prime number of parts<ref name="auto70"/>
*'''1653''' = 57th [[triangular number]],<ref name="Triangular number" /> hexagonal number,<ref name="Hexagonal number" /> number of lattice points inside a circle of radius 23<ref name="auto22"/>
*'''1654''' = number of partitions of 42 into divisors of 42<ref>{{cite OEIS|A018818|Number of partitions of n into divisors of n}}</ref>
*'''1655''' = rounded volume of a regular dodecahedron with edge length 6<ref>{{cite OEIS|A071401|Rounded volume of a regular dodecahedron with edge length n}}</ref>
*'''1656''' = 827 + 829: sum of twin prime pair<ref name="auto48"/>
*'''1657''' = [[cuban prime]],<ref name="Cuban Prime">{{Cite web|url=https://oeis.org/A002407|title=Sloane's A002407 : Cuban primes|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> prime of the form 2p-1
*'''1658''' = smallest composite that when added to sum of prime factors reaches a prime after 25 iterations<ref name="auto37"/>
*'''1659''' = number of rational numbers which can be constructed from the set of integers between 1 and 52<ref name="auto56"/>
*'''1660''' = sum of totient function for first 73 integers
*'''1661''' = 11 × 151, palindrome that is a product of two palindromic primes<ref name="auto29"/>
*'''1662''' = number of partitions of 49 into pairwise relatively prime parts<ref name="auto71"/>
*'''1663''' = a prime number and 5<sup>1663</sup> - 4<sup>1663</sup> is a 1163-digit prime number<ref>{{cite OEIS|A059802|Numbers k such that 5^k - 4^k is prime}}</ref>
*'''1664''' = k such that k, k+1 and k+2 are sums of 2 squares<ref name="auto97">{{cite OEIS|A082982|Numbers k such that k, k+1 and k+2 are sums of 2 squares}}</ref>
*'''1665''' = centered tetrahedral number<ref name="auto42"/>
*'''1666''' = largest efficient [[pandigital number]] in [[Roman numerals]] (each symbol occurs exactly once)
*'''1667''' = 228 + 1439 and the 228th prime is 1439<ref name="auto47"/>
*'''1668''' = number of partitions of 33 into parts all relatively prime to 33<ref>{{cite OEIS|A057562|Number of partitions of n into parts all relatively prime to n}}</ref>
*'''1669''' = [[super-prime]], smallest prime with a gap of exactly 24 to the next prime<ref>{{cite OEIS|A000230|smallest prime p such that there is a gap of exactly 2n between p and next prime}}</ref>
*'''1670''' = number of compositions of 12 such that at least two adjacent parts are equal<ref>{{cite OEIS|A261983|Number of compositions of n such that at least two adjacent parts are equal}}</ref>
*'''1671''' divides the sum of the first 1671 composite numbers<ref>{{cite OEIS|A053781|Numbers k that divide the sum of the first k composite numbers}}</ref>
*'''1672''' = 41<sup>2</sup> - 3<sup>2</sup>, the only way to express 1672 as a difference of prime squares<ref name="auto96"/>
*'''1673''' = RMS number<ref>{{cite OEIS|A140480|RMS numbers: numbers n such that root mean square of divisors of n is an integer}}</ref>
*'''1674''' = k such that geometric mean of phi(k) and sigma(k) is an integer<ref name="auto68"/>
*'''1675''' = Kin number<ref>{{cite OEIS|A023108|Positive integers which apparently never result in a palindrome under repeated applications of the function A056964(x)}}</ref>
*'''1676''' = number of partitions of 34 into parts each of which is used a different number of times<ref name="ReferenceG"/>
*'''1677''' = 41<sup>2</sup> - 2<sup>2</sup>, the only way to express 1677 as a difference of prime squares<ref name="auto96"/>
*'''1678''' = n such that n<sup>32</sup> + 1 is prime<ref name="auto51"/>
*'''1679''' = highly cototient number,<ref name="highly cototient" /> semiprime (23 × 73, see also [[Arecibo message]]), number of parts in all partitions of 32 into distinct parts<ref name="auto46"/>
*'''1680''' = the 17th [[highly composite number]],<ref name="Highly composite" /> number of edges in the join of two cycle graphs, both of order 40<ref name="auto89"/>
*'''1681''' = 41<sup>2</sup>, smallest number yielded by the formula ''n''<sup>2</sup> + ''n'' + 41 that is not a prime; centered octagonal number<ref name="Centered octagonal number" />
*'''1682''' = and '''1683''' is a member of a Ruth–Aaron pair (first definition)
*'''1683''' = triangular matchstick number<ref name="auto5"/>
*'''1684''' = [[centered triangular number]]<ref name="auto52"/>
*'''1685''' = 5-[[Knödel number]]<ref name="auto14"/>
*'''1686''' = <math>\sum_{k=1}^{45} \sigma(k)</math><ref name="auto38"/>
*'''1687''' = 7-Knödel number<ref name="auto21"/>
*'''1688''' = number of finite connected sets of positive integers greater than one with least common multiple 72<ref>{{cite OEIS|A286518|Number of finite connected sets of positive integers greater than one with least common multiple n}}</ref>
*'''1689''' = <math>9!!\sum_{k=0}^{4} \frac{1}{2k+1}</math><ref>{{cite OEIS|A004041|Scaled sums of odd reciprocals: (2*n + 1)!!*(Sum_{0..n} 1/(2*k + 1))}}</ref>
*'''1690''' = number of compositions of 14 into powers of 2<ref>{{cite OEIS|A023359|Number of compositions (ordered partitions) of n into powers of 2}}</ref>
*'''1691''' = the same upside down, which makes it a strobogrammatic number<ref>{{cite OEIS|A000787|Strobogrammatic numbers: the same upside down}}</ref>
*'''1692''' = coreful perfect number<ref name="auto31"/>
*'''1693''' = smallest prime > 41<sup>2</sup>.<ref name="auto57"/>
*'''1694''' = number of unimodular 2 × 2 matrices having all terms in {0,1,...,26}<ref name="auto54"/>
*'''1695''' = [[magic constant]] of ''n'' × ''n'' normal [[magic square]] and [[Eight queens puzzle|''n''-queens problem]] for ''n'' = 15. [[oeis:A000607|Number of partitions of 58 into prime parts]]
*'''1696''' = sum of totient function for first 74 integers
*'''1697''' = Friedlander-Iwaniec prime<ref name="auto12"/>
*'''1698''' = number of rooted trees with 47 vertices in which vertices at the same level have the same degree<ref name="auto28"/>
*'''1699''' = number of rooted trees with 48 vertices in which vertices at the same level have the same degree<ref name="auto28"/>

=== 1700 to 1799 ===

*'''1700''' = σ<sub>2</sub>(39): sum of squares of divisors of 39<ref name="auto76"/>
*'''1701''' = [[stirling numbers of the second kind|<math>\left\{ {8 \atop 4} \right\}</math>]], decagonal number, hull number of the U.S.S. Enterprise on ''[[Star Trek]]''
*'''1702''' = palindromic in 3 consecutive bases: 898<sub>14</sub>, 787<sub>15</sub>, 6A6<sub>16</sub>
*'''1703''' = 1703131131 / 1000077 and the divisors of 1703 are 1703, 131, 13 and 1<ref>{{cite OEIS|A224930|Numbers n such that n divides the concatenation of all divisors in descending order}}</ref>
*'''1704''' = sum of the squares of the parts in the partitions of 18 into two distinct parts<ref>{{cite OEIS|A294286|Sum of the squares of the parts in the partitions of n into two distinct parts}}</ref>
*'''1705''' = [[tribonacci number]]<ref>{{Cite web|url=https://oeis.org/A000073|title=Sloane's A000073 : Tribonacci numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref>
*'''1706''' = 1 + 4 + 16 + 64 + 256 + 1024 + 256 + 64 + 16 + 4 + 1 sum of fifth row of triangle of powers of 4<ref>{{cite OEIS|A020989|(5*4^n - 2)/3}}</ref>
*'''1707''' = number of partitions of 30 in which the number of parts divides 30<ref name="auto63"/>
*'''1708''' = 2<sup>2</sup> × 7 × 61 a number whose product of prime indices 1 × 1 × 4 × 18 is divisible by its sum of prime factors 2 + 2 + 7 + 61<ref>{{cite OEIS|A331378|Numbers whose product of prime indices is divisible by their sum of prime factors}}</ref>
*'''1709''' = first of a sequence of eight primes formed by adding [[57 (number)|57]] in the middle. 1709, 175709, 17575709, 1757575709, 175757575709, 17575757575709, 1757575757575709 and 175757575757575709 are all prime, but 17575757575757575709 = 232433 × 75616446785773
*'''1710''' = maximal number of pieces that can be obtained by cutting an annulus with 57 cuts<ref name="auto73"/>
*'''1711''' = 58th [[triangular number]],<ref name="Triangular number" /> [[centered decagonal number]]
*'''1712''' = number of irredundant sets in the 29-cocktail party graph<ref name="auto34"/>
*'''1713''' = number of aperiodic rooted trees with 12 nodes<ref>{{cite OEIS|A301700|Number of aperiodic rooted trees with n nodes}}</ref>
*'''1714''' = number of regions formed by drawing the line segments connecting any two of the 18 perimeter points of an [https://oeis.org/A331452/a331452_20.png 3 × 6 grid of squares]<ref>{{cite OEIS|A331452|number of regions (or cells) formed by drawing the line segments connecting any two of the 2*(m+n) perimeter points of an m X n grid of squares}}</ref>
*'''1715''' = k such that geometric mean of phi(k) and sigma(k) is an integer<ref name="auto68"/>
*'''1716''' = 857 + 859: sum of twin prime pair<ref name="auto48"/>
*'''1717''' = pentagonal number<ref name="Pentagonal number" />
*'''1718''' = <math>\sum_{d|12} \binom{12}{d}</math><ref>{{cite OEIS|A056045|"Sum_{d divides n}(binomial(n,d))"}}</ref>
*'''1719''' = composite [[de Polignac number]]<ref name="auto53"/>
*'''1720''' = sum of the first 31 primes
*'''1721''' = twin prime; number of squares between 42<sup>2</sup> and 42<sup>4</sup>.<ref name="auto40"/>
*'''1722''' = [[Giuga number]],<ref>{{Cite web|url=https://oeis.org/A007850|title=Sloane's A007850 : Giuga numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> pronic number<ref name="pronic number" />
*'''1723''' = [[super-prime]]
*'''1724''' = maximal number of regions the plane is divided into by drawing 42 circles<ref name="auto27"/>
*'''1725''' = 47<sup>2</sup> - 22<sup>2</sup> = (prime(15))<sup>2</sup> - (nonprime(15))<sup>2</sup><ref>{{cite OEIS|A161757|(prime(n))^2 - (nonprime(n))^2}}</ref>
*'''1726''' = number of partitions of 44 into distinct and relatively prime parts<ref>{{cite OEIS|A078374|Number of partitions of n into distinct and relatively prime parts}}</ref>
*'''1727''' = area of the 24th [https://oeis.org/A080663/a080663.jpg conjoined trapezoid]<ref name="auto13"/>
*'''[[1728 (number)|1728]]''' = the quantity expressed as 1000 in [[duodecimal]], that is, the cube of [[12 (number)|twelve]] (called a [[great gross]]), and so, the number of cubic inches in a cubic [[foot (length)|foot]], palindromic in base 11 (1331<sub>11</sub>) and 23 (363<sub>23</sub>)
*'''[[1729 (number)|1729]]''' = [[taxicab number]], Carmichael number, Zeisel number, centered cube number, [[Hardy–Ramanujan number]]. In the decimal expansion of [[E (mathematical constant)|e]] the first time all 10 digits appear in sequence starts at the 1729th digit (or 1728th decimal place). In 1979 the rock musical ''[[Hair (musical)|Hair]]'' closed on Broadway in New York City after 1729 performances. Palindromic in bases 12, 32, 36.
*'''1730''' = 3 × 24<sup>2</sup> + 2 = number of points on surface of square pyramid of side-length 24<ref name="auto58"/>
*'''1731''' = k such that geometric mean of phi(k) and sigma(k) is an integer<ref name="auto68"/>
*'''1732''' = <math>\sum_{k=0}^5 \binom{5}{k}^k</math><ref>{{cite OEIS|A167008|Sum_{0..n} C(n,k)^k}}</ref>
*'''1733''' = [[Sophie Germain prime]], palindromic in bases 3, 18, 19.
*'''1734''' = surface area of a cube of edge length 17<ref>{{cite OEIS|A033581|6*n^2}}</ref>
*'''1735''' = number of partitions of 55 such that the smallest part is greater than or equal to number of parts<ref name="auto75"/>
*'''1736''' = sum of totient function for first 75 integers, number of surface points on a cube with edge-length 18<ref name="A005897" />
*'''1737''' = pinwheel number<ref name="Pinwheel" />
*'''1738''' = number of achiral integer partitions of 52<ref name="auto64"/>
*'''1739''' = number of 1s in all partitions of 30 into odd parts<ref>{{cite OEIS|A036469|Partial sums of A000009 (partitions into distinct parts)}}</ref>
*'''1740''' = number of squares in the [[Aztec diamond]] of order 29<ref name="auto36"/>
*'''1741''' = [[super-prime]], centered square number<ref name="Centered square numbers" />
*'''1742''' = [https://mathworld.wolfram.com/PlaneDivisionbyEllipses.html number of regions] the plane is divided into by 30 ellipses<ref name="auto91"/>
*'''1743''' = [[wiener index]] of the [[windmill graph]] D(3,21)<ref name="auto90"/>
*'''1744''' = k such that k, k+1 and k+2 are sums of 2 squares<ref name="auto97"/>
*'''1745''' = 5-[[Knödel number]]<ref name="auto14"/>
*'''1746''' = number of unit-distance graphs on 8 nodes<ref>{{cite OEIS|A350507|Number of (not necessarily connected) unit-distance graphs on n nodes}}</ref>
*'''1747''' = balanced prime<ref name="Balanced prime" />
*'''1748''' = number of partitions of 55 into distinct parts in which the number of parts divides 55<ref>{{cite OEIS|A102627|Number of partitions of n into distinct parts in which the number of parts divides n}}</ref>
*'''1749''' = number of integer partitions of 33 with no part dividing all the others<ref name="auto30"/>
*'''1750''' = hypotenuse in three different Pythagorean triangles<ref name="auto101"/>
*'''1751''' = [https://oeis.org/A144391/a144391.jpg cropped hexagone]<ref name="auto44"/>
*'''1752''' = 79<sup>2</sup> - 67<sup>2</sup>, the only way to express 1752 as a difference of prime squares<ref name="auto96"/>
*'''1753''' = [[balanced prime]]<ref name="Balanced prime" />
*'''1754''' = k such that 5*2<sup>k</sup> - 1 is prime<ref name="auto69"/>
*'''1755''' = number of integer partitions of 50 whose augmented differences are distinct<ref name="auto19"/>
*'''1756''' = centered pentagonal number<ref name="Centered pentagonal" />
*'''1757''' = least number of triangles of the [[Spiral of Theodorus]] to complete 13 revolutions<ref name="auto85"/>
*'''1758''' = <math>\sum_{k=1}^{46} \sigma(k)</math><ref name="auto38"/>
*'''1759''' = [[de Polignac number|de Polignac]] prime<ref name="auto67"/>
*'''1760''' = the number of [[yard]]s in a mile
*'''1761''' = k such that k, k+1 and k+2 are products of two primes<ref name="auto81"/>
*'''1762''' = number of binary sequences of length 12 and [http://neilsloane.com/doc/CNC.pdf curling number 2]<ref>{{cite OEIS|A216955|number of binary sequences of length n and curling number k}}</ref>
*'''1763''' = number of edges in the join of two cycle graphs, both of order 41<ref name="auto89"/>
*'''1764''' = 42<sup>2</sup>
*'''1765''' = number of stacks, or planar partitions of 15<ref>{{cite OEIS|A001523|Number of stacks, or planar partitions of n; also weakly unimodal compositions of n}}</ref>
*'''1766''' = number of points on surface of octahedron with edge length 21<ref name="auto61"/>
*'''1767''' = σ(28<sup>2</sup>) = σ(35<sup>2</sup>)<ref>{{cite OEIS|A065764|Sum of divisors of square numbers}}</ref>
*'''1768''' = number of nonequivalent dissections of an hendecagon into 8 polygons by nonintersecting diagonals up to rotation<ref>{{cite OEIS|A220881|Number of nonequivalent dissections of an n-gon into n-3 polygons by nonintersecting diagonals up to rotation}}</ref>
*'''1769''' = maximal number of pieces that can be obtained by cutting an annulus with 58 cuts<ref name="auto73"/>
*'''1770''' = 59th [[triangular number]],<ref name="Triangular number" /> hexagonal number,<ref name="Hexagonal number" /> [[Seventeen Seventy, Queensland|Seventeen Seventy]], town in Australia
*'''1771''' = tetrahedral number<ref name="Tetrahedral nu"/>
*'''1772''' = centered heptagonal number,<ref name="centered heptagonal number" /> sum of totient function for first 76 integers
*'''1773''' = number of words of length 5 over the alphabet {1,2,3,4,5} such that no two even numbers appear consecutively<ref>{{cite OEIS|A154964|3*a(n-1) + 6*a(n-2)}}</ref>
*'''1774''' = number of rooted identity trees with 15 nodes and 5 leaves<ref>{{cite OEIS|A055327|Triangle of rooted identity trees with n nodes and k leaves}}</ref>
*'''1775''' = <math>\sum_{1\leq i\leq 10}prime(i)\cdot(2\cdot i-1)</math>: sum of piles of first 10 primes<ref>{{cite OEIS|A316322|Sum of piles of first n primes}}</ref>
*'''1776''' = 24th [https://oeis.org/A045944/a045944_1.jpg square star number].<ref>{{cite OEIS|A045944|Rhombic matchstick numbers: n*(3*n+2)}}</ref> The number of pieces that could be seen in a 7 × 7 × 7× 7 Rubik's Tesseract.
*'''1777''' = smallest prime > 42<sup>2</sup>.<ref name="auto57"/>
*'''1778''' = least k >= 1 such that the remainder when 6<sup>k</sup> is divided by k is 22<ref>{{cite OEIS|A127816|least k such that the remainder when 6^k is divided by k is n}}</ref>
*'''1779''' = number of achiral integer partitions of 53<ref name="auto64"/>
*'''1780''' = number of lattice paths from (0, 0) to (7, 7) using E (1, 0) and N (0, 1) as steps that horizontally cross the diagonal y = x with even many times<ref>{{cite OEIS|A005317|(2^n + C(2*n,n))/2}}</ref>
*'''1781''' = the first 1781 digits of e form a prime<ref>{{cite OEIS|A064118|Numbers k such that the first k digits of e form a prime}}</ref>
*'''1782''' = heptagonal number<ref name="heptagonal number" />
*'''1783''' = [[de Polignac number|de Polignac]] prime<ref name="auto67"/>
*'''1784''' = number of subsets of {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12} such that every pair of distinct elements has a different quotient<ref>{{cite OEIS|A325860|Number of subsets of {1..n} such that every pair of distinct elements has a different quotient}}</ref>
*'''1785''' = square pyramidal number,<ref name="Square pyramidal numbers" /> triangular matchstick number<ref name="auto5"/>
*'''1786''' = [[centered triangular number]]<ref name="auto52"/>
*'''1787''' = [[super-prime]], sum of eleven consecutive primes (137 + 139 + 149 + 151 + 157 + 163 + 167 + 173 + 179 + 181 + 191)
*'''1788''' = Euler transform of -1, -2, ..., -34<ref>{{cite OEIS|A073592|Euler transform of negative integers}}</ref>
*'''1789''' = number of wiggly sums adding to 17 (terms alternately increase and decrease or vice versa)<ref>{{cite OEIS|A025047|Alternating compositions, i.e., compositions with alternating increases and decreases, starting with either an increase or a decrease}}</ref>
*'''1790''' = number of partitions of 50 into pairwise relatively prime parts<ref name="auto71"/>
*'''1791''' = largest natural number that cannot be expressed as a sum of at most four [[hexagonal number]]s.
*'''1792''' = [[Granville number]]
*'''1793''' = number of lattice points inside a circle of radius 24<ref name="auto22"/>
*'''1794''' = nonagonal number,<ref name="Nonagonal number" /> number of partitions of 33 that do not contain 1 as a part<ref name="auto8"/>
*'''1795''' = number of heptagons with perimeter 38<ref>{{cite OEIS|A288253|Number of heptagons that can be formed with perimeter n}}</ref>
*'''1796''' = k such that geometric mean of phi(k) and sigma(k) is an integer<ref name="auto68"/>
*'''1797''' = number k such that phi(prime(k)) is a square<ref name="auto55"/>
*'''1798''' = 2 × 29 × 31 = 10<sub>2</sub> × 11101<sub>2</sub> × 11111<sub>2</sub>, which yield zero when the prime factors are xored together<ref>{{cite OEIS|A235488|Squarefree numbers which yield zero when their prime factors are xored together}}</ref>
*'''1799''' = 2 × 30<sup>2</sup> − 1 = a [https://oeis.org/A056220/a056220.jpg twin square]<ref name="auto83"/>

=== 1800 to 1899 ===

*'''1800''' = pentagonal pyramidal number,<ref name="Pentagonal pyramidal number" /> [[Achilles number]], also, in da Ponte's ''[[Don Giovanni]]'', the number of women Don Giovanni had slept with so far when confronted by Donna Elvira, according to Leporello's tally
*'''1801''' = [[cuban prime]], sum of five and nine consecutive primes (349 + 353 + 359 + 367 + 373 and 179 + 181 + 191 + 193 + 197 + 199 + 211 + 223 + 227)<ref name="Cuban Prime" />
*'''1802''' = 2 × 30<sup>2</sup> + 2 = number of points on surface of tetrahedron with edge length 30,<ref name="auto59"/> number of partitions of 30 such that the number of odd parts is a part<ref name="auto72"/>
*'''1803''' = number of [[polyhex (mathematics)|decahexes]] that tile the plane isohedrally but not by translation or by 180-degree rotation (Conway criterion)<ref>{{cite OEIS|A075213|Number of polyhexes with n cells that tile the plane isohedrally but not by translation or by 180-degree rotation (Conway criterion)}}</ref>
*'''1804''' = [[oeis:A006316|number k such that k^64 + 1 is prime]]
*'''1805''' = number of squares between 43<sup>2</sup> and 43<sup>4</sup>.<ref name="auto40"/>
*'''1806''' = pronic number,<ref name="pronic number" /> product of first four terms of [[Sylvester's sequence]], [[primary pseudoperfect number]],<ref>{{Cite web|url=https://oeis.org/A054377|title=Sloane's A054377 : Primary pseudoperfect numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> only number for which ''n'' equals the denominator of the ''n''th [[Bernoulli number]],<ref>Kellner, Bernard C.; [http://www.bernoulli.org/~bk/denombneqn.pdf 'The equation denom(B<sub>''n''</sub>) = ''n'' has only one solution']</ref> [[Schröder number]]<ref>{{Cite OEIS|1=A006318|2=Large Schröder numbers|access-date=2016-05-22}}</ref>
*'''1807''' = fifth term of Sylvester's sequence<ref>{{Cite web|url=https://oeis.org/A000058|title=Sloane's A000058 : Sylvester's sequence|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref>
*'''1808''' = maximal number of regions the plane is divided into by drawing 43 circles<ref name="auto27"/>
*'''1809''' = sum of first 17 [[super-prime]]s<ref>{{cite OEIS|A083186|Sum of first n primes whose indices are primes}}</ref>
*'''1810''' = <math>\sum_{k=0}^4 \binom{4}{k}^4</math><ref>{{cite OEIS|A005260|Sum_{0..n} binomial(n,k)^4}}</ref>
*'''1811''' = Sophie Germain prime
*'''1812''' = n such that n<sup>32</sup> + 1 is prime<ref name="auto51"/>
*'''1813''' = number of [[polyominoes]] with 26 cells, symmetric about two orthogonal axes<ref>{{cite OEIS|A056877|Number of polyominoes with n cells, symmetric about two orthogonal axes}}</ref>
*'''1814''' = 1 + 6 + 36 + 216 + 1296 + 216 + 36 + 6 + 1 = sum of 4th row of triangle of powers of six<ref>{{cite OEIS|A061801|(7*6^n - 2)/5}}</ref>
*'''1815''' = polygonal chain number <math>\#(P^3_{2,1})</math><ref>{{cite OEIS|A152927|Number of sets (in the Hausdorff metric geometry) at each location between two sets defining a polygonal configuration consisting of k 4-gonal polygonal components chained with string components of length 1 as k varies}}</ref>
*'''1816''' = number of strict partions of 44<ref name="auto20"/>
*'''1817''' = total number of prime parts in all partitions of 20<ref>{{cite OEIS|A037032|Total number of prime parts in all partitions of n}}</ref>
*'''1818''' = n such that n<sup>32</sup> + 1 is prime<ref name="auto51"/>
*'''1819''' = sum of the first 32 primes, minus 32<ref>{{cite OEIS|A101301|The sum of the first n primes, minus n}}</ref>
*'''1820''' = pentagonal number,<ref name="Pentagonal number" /> pentatope number,<ref name="Pentatope number" /> number of compositions of 13 whose run-lengths are either weakly increasing or weakly decreasing<ref name="auto1">{{cite OEIS|A332835|Number of compositions of n whose run-lengths are either weakly increasing or weakly decreasing|access-date=2022-06-02}}</ref>
*'''1821''' = member of the Mian–Chowla sequence<ref name=Mian-Chowla />
*'''1822''' = number of integer partitions of 43 whose distinct parts are connected<ref name="auto86"/>
*'''1823''' = [[super-prime]], safe prime<ref name="Safe primes" />
*'''1824''' = 43<sup>2</sup> - 5<sup>2</sup>, the only way to express 1824 as a difference of prime squares<ref name="auto96"/>
*'''1825''' = [[octagonal number]]<ref name="auto17"/>
*'''1826''' = decagonal pyramidal number<ref name="auto62"/>
*'''1827''' = [[vampire number]]<ref name="Vampire number" />
*'''1828''' = [[meandric number]], [[open meandric number]], [[Mathematical coincidence|appears twice]] in the first 10 decimal digits of ''[[E (mathematical constant)|e]]''
*'''1829''' = composite [[de Polignac number]]<ref name="auto53"/>
*'''1830''' = 60th [[triangular number]]<ref name="Triangular number" />
*'''1831''' = smallest prime with a gap of exactly 16 to next prime (1847)<ref>{{cite OEIS|A000230|smallest prime p such that there is a gap of exactly 2n between p and next prime, or -1 if no such prime exists}}</ref>
*'''1832''' = sum of totient function for first 77 integers
*'''1833''' = number of atoms in a decahedron with 13 shells<ref>{{cite OEIS|A004068|Number of atoms in a decahedron with n shells}}</ref>
*'''1834''' = octahedral number,<ref name="Octahedral number" /> sum of the cubes of the first five primes
*'''1835''' = absolute value of numerator of <math>D_6^{(5)}</math><ref>{{cite OEIS|A001905|From higher-order Bernoulli numbers: absolute value of numerator of D-number D2n(2n-1)}}</ref>
*'''1836''' = factor by which a [[proton]] is more massive than an [[electron]]
*'''1837''' = star number<ref name="Centered 12-gonal numbers" />
*'''1838''' = number of unimodular 2 × 2 matrices having all terms in {0,1,...,27}<ref name="auto54"/>
*'''1839''' = <math>\lfloor \sqrt[3]{13!} \rfloor </math><ref>{{cite OEIS|A214083|floor(n!^(1/3))}}</ref>
*'''1840''' = 43<sup>2</sup> - 3<sup>2</sup>, the only way to express 1840 as a difference of prime squares<ref name="auto96"/>
*'''1841''' = solution to the postage stamp problem with 3 denominations and 29 stamps,<ref>{{cite OEIS|A001208|solution to the postage stamp problem with 3 denominations and n stamps}}</ref> Mertens function zero
*'''1842''' = number of unlabeled rooted trees with 11 nodes<ref>{{cite OEIS|A000081|Number of unlabeled rooted trees with n nodes (or connected functions with a fixed point)}}</ref>
*'''1843''' = k such that phi(k) is a perfect cube,<ref>{{cite OEIS|A039771|Numbers k such that phi(k) is a perfect cube}}</ref> Mertens function zero
*'''1844''' = 3<sup>7</sup> - 7<sup>3</sup>,<ref>{{cite OEIS|A024026|3^n - n^3}}</ref> Mertens function zero
*'''1845''' = number of partitions of 25 containing at least one prime,<ref>{{cite OEIS|A235945|Number of partitions of n containing at least one prime}}</ref> Mertens function zero
*'''1846''' = sum of first 49 composite numbers<ref name="auto94"/>
*'''1847''' = [[super-prime]]
*'''1848''' = number of edges in the join of two cycle graphs, both of order 42<ref name="auto89"/>
*'''1849''' = 43<sup>2</sup>, palindromic in base 6 (= 12321<sub>6</sub>), centered octagonal number<ref name="Centered octagonal number" />
*'''1850''' = [[oeis:A000607|Number of partitions of 59 into prime parts]]
*'''1851''' = sum of the first 32 primes
*'''1852''' = number of quantales on 5 elements, up to isomorphism<ref>{{cite OEIS|A354493|Number of quantales on n elements, up to isomorphism}}</ref>
*'''1853''' = sum of primitive roots of 27-th prime,<ref>{{cite OEIS|A088144|Sum of primitive roots of n-th prime}}</ref> Mertens function zero
*'''1854''' = number of permutations of 7 elements with no fixed points,<ref>{{cite OEIS|A000166|Subfactorial or rencontres numbers, or derangements: number of permutations of n elements with no fixed points}}</ref> Mertens function zero
*'''1855''' = rencontres number: number of permutations of [7] with exactly one fixed point<ref>{{cite OEIS|A000240|Rencontres numbers: number of permutations of [n] with exactly one fixed point}}</ref>
*'''1856''' = sum of totient function for first 78 integers
*'''1857''' = Mertens function zero, pinwheel number<ref name="Pinwheel" />
*'''1858''' = number of 14-carbon alkanes C<sub>14</sub>H<sub>30</sub> ignoring stereoisomers<ref>{{cite OEIS|A000602|Number of n-node unrooted quartic trees; number of n-carbon alkanes C(n)H(2n+2) ignoring stereoisomers}}</ref>
*'''1859''' = composite [[de Polignac number]]<ref name="auto53"/>
*'''1860''' = number of squares in the [[Aztec diamond]] of order 30<ref>{{cite web|url=https://mathworld.wolfram.com/AztecDiamond.html|title="Aztec Diamond"|access-date=2022-09-20}}</ref>
*'''1861''' = centered square number,<ref name="Centered square numbers" /> Mertens function zero
*'''1862''' = Mertens function zero, forms a Ruth–Aaron pair with 1863 under second definition
*'''1863''' = Mertens function zero, forms a Ruth–Aaron pair with 1862 under second definition
*'''1864''' = Mertens function zero, <math>\frac{1864!-2}{2}</math> is a prime<ref>{{cite OEIS|A082671|Numbers n such that (n!-2)/2 is a prime}}</ref>
*'''1865''' = 12345<sub>6</sub>: Largest [[senary]] metadrome (number with digits in strict ascending order in base 6)<ref>{{cite OEIS|A023811|Largest metadrome (number with digits in strict ascending order) in base n}}</ref>
*'''1866''' = Mertens function zero, number of plane partitions of 16 with at most two rows<ref>{{cite OEIS|A000990|Number of plane partitions of n with at most two rows}}</ref>
*'''1867''' = prime [[de Polignac number]]<ref name="auto67"/>
*'''1868''' = smallest number of complexity 21: smallest number requiring 21 1's to build using +, * and ^<ref name="auto49"/>
*'''1869''' = Hultman number: S<sub>H</sub>(7, 4)<ref>{{cite OEIS|A164652|Hultman numbers}}</ref>
*'''1870''' = decagonal number<ref name="Decagonal" />
*'''1871''' = the first prime of the 2 consecutive twin prime pairs: (1871, 1873) and (1877, 1879)<ref>{{cite OEIS|A007530|Prime quadruples: numbers k such that k, k+2, k+6, k+8 are all prime}}</ref>
*'''1872''' = first Zagreb index of the complete graph K<sub>13</sub><ref name="auto100"/>
*'''1873''' = number of Narayana's cows and calves after 21 years<ref name="auto98"/>
*'''1874''' = area of the 25th [https://oeis.org/A080663/a080663.jpg conjoined trapezoid]<ref name="auto13"/>
*'''1875''' = 50<sup>2</sup> - 25<sup>2</sup>
*'''1876''' = [[oeis:A006316|number k such that k^64 + 1 is prime]]
*'''1877''' = number of partitions of 39 where 39 divides the product of the parts<ref>{{cite OEIS|A057568|Number of partitions of n where n divides the product of the parts}}</ref>
*'''1878''' = n such that n<sup>32</sup> + 1 is prime<ref name="auto51"/>
*'''1879''' = a prime with square index<ref>{{cite OEIS|A011757|prime(n^2)}}</ref>
*'''1880''' = the 10th element of the self convolution of Lucas numbers<ref>{{cite OEIS|A004799|Self convolution of Lucas numbers}}</ref>
*'''1881''' = [[Triaugmented triangular prism|tricapped prism]] number<ref>{{cite OEIS|A005920|Tricapped prism numbers}}</ref>
*'''1882''' = number of [[Linear separability|linearly separable]] [[Boolean functions]] in 4 variables<ref>{{cite OEIS|A000609|Number of threshold functions of n or fewer variables}}</ref>
*'''1883''' = number of conjugacy classes in the alternating group A<sub>28</sub><ref name="auto33"/>
*'''1884''' = k such that 5*2<sup>k</sup> - 1 is prime<ref name="auto69"/>
*'''1885''' = Zeisel number<ref name="Zeisel number" />
*'''1886''' = number of partitions of 6<sup>4</sup> into fourth powers<ref>{{cite OEIS|A259793|Number of partitions of n^4 into fourth powers}}</ref>
*'''1887''' = number of edges in the [[:File:Hexagonal triangle.png|hexagonal triangle]] T(34)<ref name="auto60"/>
*'''1888''' = primitive abundant number ([[abundant number]] all of whose proper divisors are [[deficient numbers]])<ref name="auto92"/>
*'''1889''' = Sophie Germain prime, highly cototient number<ref name="highly cototient" />
*'''1890''' = triangular matchstick number<ref name="auto5"/>
*'''1891''' = 61st [[triangular number]],<ref name="Triangular number" /> sum of 5 consecutive primes ({{math|1=367 + 373 + 379 + 383 + 389}}) hexagonal number,<ref name="Hexagonal number" /> centered pentagonal number,<ref name="Centered pentagonal" /> [[centered triangular number]]<ref name="auto52"/>
*'''1892''' = pronic number<ref name="pronic number" />
*'''1893''' = 44<sup>2</sup> - 44 + 1 = H<sub>44</sub> (the 44th Hogben number)<ref name="auto77"/>
*'''1894''' = maximal number of regions the plane is divided into by drawing 44 circles<ref name="auto27"/>
*'''1895''' = Stern-Jacobsthal number<ref name="auto15"/>
*'''1896''' = member of the Mian-Chowla sequence<ref name=Mian-Chowla />
*'''1897''' = member of Padovan sequence,<ref name="Padovan sequence" /> number of triangle-free graphs on 9 vertices<ref>{{cite OEIS|A006785|Number of triangle-free graphs on n vertices}}</ref>
*'''1898''' = smallest multiple of n whose digits sum to 26<ref>{{cite OEIS|A002998|Smallest multiple of n whose digits sum to n}}</ref>
*'''1899''' = [https://oeis.org/A144391/a144391.jpg cropped hexagone]<ref name="auto44"/>

=== 1900 to 1999 ===

*'''1900''' = number of primes <= 2<sup>14</sup><ref name="auto3"/>
*'''1901''' = Sophie Germain prime, [[centered decagonal number]]
*'''1902''' = number of symmetric plane partitions of 27<ref>{{cite OEIS|A005987|Number of symmetric plane partitions of n}}</ref>
*'''1903''' = generalized Catalan number<ref>{{cite OEIS|A023431|Generalized Catalan Numbers}}</ref>
*'''1904''' = number of flat partitions of 43<ref name="auto26"/>
*'''1905''' = [[Fermat pseudoprime]]<ref name="auto93"/>
*'''1906''' = number n such that 3<sup>n</sup> - 8 is prime<ref>{{cite OEIS|A217135|Numbers n such that 3^n - 8 is prime}}</ref>
*'''1907''' = safe prime,<ref name="Safe primes" /> balanced prime<ref name="Balanced prime" />
*'''1908''' = coreful perfect number<ref name="auto31"/>
*'''1909''' = [[hyperperfect number]]<ref>{{Cite web|url=https://oeis.org/A034897|title=Sloane's A034897 : Hyperperfect numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref>
*'''1910''' = number of compositions of 13 having exactly one fixed point<ref>{{cite OEIS|A240736|Number of compositions of n having exactly one fixed point}}</ref>
*'''1911''' = heptagonal pyramidal number<ref name="auto82"/>
*'''1912''' = size of 6th maximum raising after one blind in pot-limit poker<ref>{{cite OEIS|A007070|4*a(n-1) - 2*a(n-2)}}</ref>
*'''1913''' = [[super-prime]], Honaker prime<ref name="auto39"/>
*'''1914''' = number of bipartite partitions of 12 white objects and 3 black ones<ref>{{cite OEIS|A000412|Number of bipartite partitions of n white objects and 3 black ones}}</ref>
*'''1915''' = number of nonisomorphic semigroups of order 5<ref>{{cite OEIS|A027851|Number of nonisomorphic semigroups of order n}}</ref>
*'''1916''' = sum of first 50 composite numbers<ref name="auto94"/>
*'''1917''' = number of partitions of 51 into pairwise relatively prime parts<ref name="auto71"/>
*'''1918''' = heptagonal number<ref name="heptagonal number" />
*'''1919''' = smallest number with reciprocal of period length 36 in base 10<ref>{{cite OEIS|A003060|Smallest number with reciprocal of period length n in decimal (base 10)}}</ref>
*'''1920''' = [[oeis:A006002|sum of the nontriangular numbers between successive triangular numbers 120 and 136]],
*'''1921''' = 4-dimensional centered cube number<ref>{{cite OEIS|A008514|4-dimensional centered cube numbers}}</ref>
*'''1922''' = Area of a square with diagonal 62<ref name="area of a square with diagonal 2n"/>
*'''1923''' = 2 × 31<sup>2</sup> + 1 = number of different 2 X 2 determinants with integer entries from 0 to 31<ref name="auto32"/>
*'''1924''' = 2 × 31<sup>2</sup> + 2 = number of points on surface of tetrahedron with edge length 31,<ref name="auto59"/> sum of the first 36 semiprimes<ref>{{cite OEIS|A062198|Sum of the first n semiprimes}}</ref>
*'''1925''' = number of ways to write 24 as an orderless product of orderless sums<ref name="auto79"/>
*'''1926''' = pentagonal number<ref name="Pentagonal number" />
*'''1927''' = 2<sup>11</sup> - 11<sup>2</sup><ref>{{cite OEIS|A024012|2^n - n^2}}</ref>
*'''1928''' = number of distinct values taken by 2^2^...^2 (with 13 2's and parentheses inserted in all possible ways)<ref>{{cite OEIS|A002845|Number of distinct values taken by 2^2^...^2 (with n 2's and parentheses inserted in all possible ways)}}</ref>
*'''1929''' = Mertens function zero, number of integer partitions of 42 whose distinct parts are connected<ref name="auto86"/>
*'''1930''' = number of pairs of consecutive integers x, x+1 such that all prime factors of both x and x+1 are at most 53<ref name="auto80"/>
*'''1931''' = Sophie Germain prime
*'''1932''' = number of partitions of 40 into prime power parts<ref name="auto87"/>
*'''1933''' = centered heptagonal number,<ref name="centered heptagonal number" /> Honaker prime<ref name="auto39"/>
*'''1934''' = sum of totient function for first 79 integers
*'''1935''' = number of edges in the join of two cycle graphs, both of order 43<ref name="auto89"/>
*'''1936''' = 44<sup>2</sup>, 18-gonal number,<ref>{{Cite web|url=https://oeis.org/A051870|title=Sloane's A051870 : 18-gonal numbers|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2016-06-12}}</ref> 324-gonal number.
*'''1937''' = number of chiral n-ominoes in 12-space, one cell labeled<ref>{{cite OEIS|A045648|Number of chiral n-ominoes in (n-1)-space, one cell labeled}}</ref>
*'''1938''' = Mertens function zero, number of points on surface of octahedron with edge length 22<ref name="auto61"/>
*'''1939''' = 7-Knödel number<ref name="auto21"/>
*'''1940''' = the Mahonian number: T(8, 9)<ref name="A008302" />
*'''1941''' = maximal number of regions obtained by joining 16 points around a circle by straight lines<ref>{{cite OEIS|A000127|Maximal number of regions obtained by joining n points around a circle by straight lines. Also number of regions in 4-space formed by n-1 hyperplanes}}</ref>
*'''1942''' = number k for which 10k + 1, 10k + 3, 10k + 7, 10k + 9 and 10k + 13 are primes<ref>{{cite OEIS|A178084|Numbers k for which 10k + 1, 10k + 3, 10k + 7, 10k + 9 and 10k + 13 are primes}}</ref>
*'''1943''' = largest number not the sum of distinct tetradecagonal numbers<ref name="auto24">{{cite OEIS|A007419|Largest number not the sum of distinct n-th-order polygonal numbers}}</ref>
*'''1944''' = [[3-smooth]] number (2<sup>3</sup>×3<sup>5</sup>), [[Achilles number]]<ref name="Achilles" />
*'''1945''' = number of partitions of 25 into relatively prime parts such that multiplicities of parts are also relatively prime<ref>{{cite OEIS|A100953|Number of partitions of n into relatively prime parts such that multiplicities of parts are also relatively prime}}</ref>
*'''1946''' = number of surface points on a cube with edge-length 19<ref name="A005897" />
*'''1947''' = k such that 5·2<sup>k</sup> + 1 is a prime factor of a Fermat number 2<sup>2<sup>m</sup></sup> + 1 for some m<ref>{{cite OEIS|A226366|Numbers k such that 5*2^k + 1 is a prime factor of a Fermat number 2^(2^m) + 1 for some m}}</ref>
*'''1948''' = number of strict solid partitions of 20<ref name="auto43"/>
*'''1949''' = smallest prime > 44<sup>2</sup>.<ref name="auto57"/>
*'''1950''' = <math>1 \cdot 2 \cdot 3 + 4 \cdot 5 \cdot 6 + 7 \cdot 8 \cdot 9 + 10 \cdot 11 \cdot 12</math>,<ref>{{cite OEIS|A319014|1*2*3 + 4*5*6 + 7*8*9 + 10*11*12 + 13*14*15 + 16*17*18 + ... + (up to n)}}</ref> largest number not the sum of distinct pentadecagonal numbers<ref name="auto24"/>
*'''1951''' = cuban prime<ref name="Cuban Prime" />
*'''1952''' = number of covers of {1, 2, 3, 4}<ref>{{cite OEIS|A055621|Number of covers of an unlabeled n-set}}</ref>
*'''1953''' = 62nd [[triangular number]]<ref name="Triangular number" />
*'''1954''' = number of sum-free subsets of {1, ..., 16}<ref name="auto41"/>
*'''1955''' = number of partitions of 25 with at least one distinct part<ref name="auto66"/>
*'''1956''' = nonagonal number<ref name="Nonagonal number" />
*'''1957''' = <math>\sum_{k=0}^{6} \frac{6!}{k!}</math> = total number of ordered k-tuples (k=0,1,2,3,4,5,6) of distinct elements from an 6-element set<ref>{{cite OEIS|A000522|Total number of ordered k-tuples of distinct elements from an n-element set}}</ref>
*'''1958''' = number of partitions of 25<ref name="auto35"/>
*'''1959''' = Heptanacci-Lucas number<ref>{{cite OEIS|A104621|Heptanacci-Lucas numbers}}</ref>
*'''1960''' = number of parts in all partitions of 33 into distinct parts<ref name="auto46"/>
*'''1961''' = number of lattice points inside a circle of radius 25<ref name="auto22"/>
*'''1962''' = number of edges in the join of the complete graph K<sub>36</sub> and the cycle graph C<sub>36</sub><ref>{{cite OEIS|A005449|Second pentagonal numbers}}</ref>
*'''1963'''! - 1 is prime<ref>{{cite OEIS|A002982|Numbers n such that n! - 1 is prime}}</ref>
*'''1964''' = number of linear forests of planted planar trees with 8 nodes<ref>{{cite OEIS|A030238|Backwards shallow diagonal sums of Catalan triangle A009766}}</ref>
*'''1965''' = total number of parts in all partitions of 17<ref name="auto16"/>
*'''1966''' = sum of totient function for first 80 integers
*'''1967''' = least edge-length of a square dissectable into at least 30 squares in the Mrs. Perkins's quilt problem<ref>{{cite OEIS|A089046|Least edge-length of a square dissectable into at least n squares in the Mrs. Perkins's quilt problem}}</ref>
*'''σ(1968)''' = σ(1967) + σ(1966)<ref>{{cite OEIS|A065900|Numbers n such that sigma(n) equals sigma(n-1) + sigma(n-2)}}</ref>
*'''1969''' = Only value less than four million for which a "mod-ification" of the standard [[Ackermann Function]] does not stabilize<ref>{{cite journal
| title=A Mod-n Ackermann Function, or What's So Special About 1969?
| url=https://archive.org/details/sim_american-mathematical-monthly_1993-02_100_2/page/180
| author=Jon Froemke
| author2=Jerrold W. Grossman
| name-list-style=amp|journal=[[The American Mathematical Monthly]]
| volume=100|issue=2|date=Feb 1993|pages= 180–183
| publisher=Mathematical Association of America
| jstor=2323780|doi=10.2307/2323780}}</ref>
*'''1970''' = number of compositions of two types of 9 having no even parts<ref>{{cite OEIS|A052542|2*a(n-1) + a(n-2)}}</ref>
*'''1971''' = <math>3^7-6^3</math><ref>{{cite OEIS|A024069|6^n - n^7}}</ref>
*'''1972''' = n such that <math>\frac{n^{37}-1}{n-1}</math> is prime<ref>{{cite OEIS|A217076|Numbers n such that (n^37-1)/(n-1) is prime}}</ref>
*{{anchor|1973}} '''1973''' = Sophie Germain prime, [[Leonardo prime]]
*'''1974''' = number of binary vectors of length 17 containing no singletons<ref name="auto50"/>
*'''1975''' = number of partitions of 28 with nonnegative rank<ref name="auto18"/>
*'''1976''' = [[octagonal number]]<ref name="auto17"/>
*'''1977''' = number of non-isomorphic multiset partitions of weight 9 with no singletons<ref>{{cite OEIS|A302545|Number of non-isomorphic multiset partitions of weight n with no singletons}}</ref>
*'''1978''' = n such that n | (3<sup>n</sup> + 5)<ref>{{cite OEIS|A277288|Positive integers n such that n divides (3^n + 5)}}</ref>
*'''1979''' = number of squares between 45<sup>2</sup> and 45<sup>4</sup>,<ref name="auto40"/> smallest number that is the sum of 4 positive cubes in at least 4 ways<ref>{{cite OEIS|A343971|Numbers that are the sum of four positive cubes in four or more ways}}</ref>
*'''[[1980 (number)|1980]]''' = pronic number,<ref name="pronic number" /> highly abundant number with a greater sum of proper divisors than all smaller numbers<ref>{{cite OEIS|A034090|Numbers k whose sum of proper divisors exceeds that of all smaller numbers}}</ref>
*'''1981''' = pinwheel number,<ref name="Pinwheel" /> central polygonal number<ref name="auto11"/>
*'''1982''' = maximal number of regions the plane is divided into by drawing 45 circles,<ref name="auto27"/> a number with the property that 3<sup>1982</sup> - 1982 is prime<ref>{{cite OEIS|A058037|Numbers k such that 3^k - k is prime}}</ref>
*'''1983''' = skiponacci number<ref name="auto25"/>
*'''1984''' = 11111000000 in [[Binary numeral system|binary]], nonunitary perfect number,<ref>{{cite OEIS|A064591|Nonunitary perfect numbers}}</ref> see also: [[1984|1984 (disambiguation)]]
*'''1985''' = [[centered square number]]<ref name="Centered square numbers" />
*'''1986''' = number of ways to write 25 as an orderless product of orderless sums<ref name="auto79"/>
*'''[[1987 (number)|1987]]''' = 300th [[prime number]]
*'''1988''' = sum of the first 33 primes,<ref>{{cite OEIS|A007504|Sum of the first n primes}}</ref> sum of the first 51 composite numbers<ref>{{cite OEIS|A053767|Sum of the first n composite numbers}}</ref>
*'''1989''' = number of balanced primes less than 100,000,<ref>{{cite OEIS|A096711|Number of balanced primes less than 10^n.}}</ref> number of 9-step mappings with 4 inputs<ref name="auto95"/>
*'''1990''' = [[Stella octangula number]]
*'''1991''' = 11 × 181, the 46th [[:File:1991 A187220 46.png|Gullwing]] number,<ref>{{cite OEIS|A187220|Gullwing sequence}}</ref> palindromic composite number with only palindromic prime factors<ref>{{cite OEIS|A046351|Palindromic composite numbers with only palindromic prime factors}}</ref>
*'''1992''' = number of nonisomorphic sets of nonempty subsets of a 4-set<ref>{{cite OEIS|A000612|Number of P-equivalence classes of switching functions of n or fewer variables, divided by 2}}</ref>
*'''1993''' = a number with the property that 4<sup>1993</sup> - 3<sup>1993</sup> is prime,<ref>{{oeis|A059801}}</ref> number of partitions of 30 into a prime number of parts<ref name="auto70"/>
*'''1994''' = Glaisher's function W(37)<ref>{{cite OEIS|A002470|Glaisher's function W(n)}}</ref>
*'''1995''' = number of unlabeled graphs on 9 vertices with independence number 6<ref>{{cite OEIS|A263341|Triangle read by rows: T(n,k) is the number of unlabeled graphs on n vertices with independence number k}}</ref>
*'''1996''' = a number with the property that (1996! + 3)/3 is prime<ref>{{cite OEIS|A089085|Numbers k such that (k! + 3)/3 is prime}}</ref>
*'''1997''' = <math>\sum_{k=1}^{21} {k \cdot \phi(k)}</math><ref>{{cite OEIS|A011755|Sum_{1..n} k*phi(k)}}</ref>
*'''1998''' = triangular matchstick number<ref name="auto5"/>
*'''1999''' = [[centered triangular number]],<ref>{{cite OEIS|A005448|Centered triangular numbers: 3n(n-1)/2 + 1}}</ref> number of [[Regular polygon|regular]] forms in a [[Myriagon|myriagram]].

=== Prime numbers ===

There are 135 [[prime number]]s between 1000 and 2000:<ref>{{Cite OEIS|A038823|Number of primes between n*1000 and (n+1)*1000}}</ref><ref>{{cite web |last=Stein |first=William A. |author-link=William A. Stein |title=The Riemann Hypothesis and The Birch and Swinnerton-Dyer Conjecture |url=https://wstein.org/talks/2017-02-10-wing-rh_and_bsd/ |website=wstein.org |date=10 February 2017 |access-date=6 February 2021}}</ref>
:1009, 1013, 1019, 1021, 1031, 1033, 1039, 1049, 1051, 1061, 1063, 1069, 1087, 1091, 1093, 1097, 1103, 1109, 1117, 1123, 1129, 1151, 1153, 1163, 1171, 1181, 1187, 1193, 1201, 1213, 1217, 1223, 1229, 1231, 1237, 1249, 1259, 1277, 1279, 1283, 1289, 1291, 1297, 1301, 1303, 1307, 1319, 1321, 1327, 1361, 1367, 1373, 1381, 1399, 1409, 1423, 1427, 1429, 1433, 1439, 1447, 1451, 1453, 1459, 1471, 1481, 1483, 1487, 1489, 1493, 1499, 1511, 1523, 1531, 1543, 1549, 1553, 1559, 1567, 1571, 1579, 1583, 1597, 1601, 1607, 1609, 1613, 1619, 1621, 1627, 1637, 1657, 1663, 1667, 1669, 1693, 1697, 1699, 1709, 1721, 1723, 1733, 1741, 1747, 1753, 1759, 1777, 1783, 1787, 1789, 1801, 1811, 1823, 1831, 1847, 1861, 1867, 1871, 1873, 1877, 1879, 1889, 1901, 1907, 1913, 1931, 1933, 1949, 1951, 1973, 1979, 1987, 1993, 1997, 1999

== Notes ==
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== References ==

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