cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-9 of 9 results.

A048364 a(n) is the index of the smallest triangular number containing exactly n 9's.

Original entry on oeis.org

13, 44, 631, 1413, 28282, 76419, 282842, 1414213, 4471955, 31616419, 446313656, 1414001413, 6276925986, 44710913656, 44721356419, 632129732586, 527257052109, 14141923468538, 44698881216419, 199449241362306, 141421356237309, 4690415742340969, 42426404749855955, 44703449755024186, 1095435073375871053
Offset: 1

Views

Author

Patrick De Geest, Mar 15 1999

Keywords

Crossrefs

Programs

  • Mathematica
    nsmall = Table[Infinity, 20];
    For[i = 0, i <= 10^6, i++, p = PolygonalNumber[i];
      n0 = Count[IntegerDigits[p], 9];
      If[nsmall[[n0]] > i, nsmall[[n0]] = i]];
    ReplaceAll[nsmall, Infinity -> "?"] (* Robert Price, Mar 22 2020 *)

Extensions

a(13)-a(15) from Lars Blomberg, May 16 2011
a(16)-a(18) from Giovanni Resta, Oct 30 2019
a(19)-a(25) from Max Alekseyev, Mar 07 2025

A036521 Smallest triangular number containing exactly n 4's.

Original entry on oeis.org

45, 4465, 144453, 544446, 427444941, 414446445, 4440447441, 444344944456, 4404424444435, 1046444944404441, 14546344444444945, 441441444448564440, 4445444444946443841, 444438244043444444046, 4444844454444484014645, 44641424644444444411441, 4024414288444444444404441, 44448461444441444448442420
Offset: 1

Views

Author

Keywords

Crossrefs

Programs

  • Mathematica
    nsmall = Table[Infinity, 20];
    For[i = 0, i <= 10^6, i++, p = PolygonalNumber[i];
      n0 = Count[IntegerDigits[p], 4];
      If[nsmall[[n0]] > p, nsmall[[n0]] = p]];
    ReplaceAll[nsmall, Infinity -> "?"] (* Robert Price, Mar 22 2020 *)

Extensions

a(12)-a(18) from Giovanni Resta, Oct 30 2019

A036525 Smallest triangular number containing exactly n 8's.

Original entry on oeis.org

28, 3828, 48828, 828828, 55888878, 3288888856, 78888885078, 388884828828, 13889888887878, 28888888883865, 8980885988888880, 88838888988888990, 983888888888812878, 8838888986888887878, 894885888888885888855, 78888888822845888188878, 1888886085781088888888878, 18788848888888828885888126
Offset: 1

Views

Author

Keywords

Crossrefs

Programs

  • Mathematica
    nsmall = Table[Infinity, 20];
    For[i = 0, i <= 10^6, i++, p = PolygonalNumber[i];
      n0 = Count[IntegerDigits[p], 8];
      If[nsmall[[n0]] > p, nsmall[[n0]] = p]];
    ReplaceAll[nsmall, Infinity -> "?"] (* Robert Price, Mar 22 2020 *)

Extensions

a(13)-a(18) from Giovanni Resta, Oct 30 2019

A036518 Smallest triangular number containing exactly n 1's.

Original entry on oeis.org

1, 171, 1711, 105111, 1188111, 18111171, 1111160511, 11161151121, 111111101310, 11311511141161, 121111912011111, 11111811011411671, 11101111131911151, 11111111111113201, 111111312111373411111, 1119711111215111121171, 111112117111126711111195, 1141011111112731111616111
Offset: 1

Views

Author

Keywords

Crossrefs

Programs

  • Mathematica
    nsmall = Table[Infinity, 20];
    For[i = 0, i <= 10^6, i++, p = PolygonalNumber[i];
      n0 = Count[IntegerDigits[p], 1];
      If[nsmall[[n0]] > p, nsmall[[n0]] = p]];
    ReplaceAll[nsmall, Infinity -> "?"] (* Robert Price, Mar 22 2020 *)
    Module[{nn=5*10^6,tr},tr={#,DigitCount[#,10,1]}&/@Accumulate[Range[ nn]]; Table[ SelectFirst[tr,#[[2]]==k&],{k,10}]][[;;,1]] (* The program generates the first 10 terms of the sequence. *) (* Harvey P. Dale, Sep 01 2024 *)

Formula

a(n) = A000217(A048356(n)). - Michel Marcus, Aug 12 2014

Extensions

Definition clarified by Robert Israel, Aug 10 2014
a(15)-a(16) from A048356 by Michel Marcus, Aug 12 2014
a(17)-a(18) from Giovanni Resta, Oct 30 2019

A036519 Smallest triangular number containing exactly n 2's.

Original entry on oeis.org

21, 1225, 23220, 212226, 22121226, 2202322528, 21222223210, 202222242820, 22122952222920, 229222922294226, 2221228522222920, 222322222025202925, 222212284222222920, 22222122841222222920, 2092226022222222442221, 22222222042522220020225, 622222207421222222222253, 22222212062122272422225226
Offset: 1

Views

Author

Keywords

Crossrefs

Programs

  • Mathematica
    nsmall = Table[Infinity, 20];
    For[i = 0, i <= 10^6, i++, p = PolygonalNumber[i];
      n0 = Count[IntegerDigits[p], 2];
      If[nsmall[[n0]] > p, nsmall[[n0]] = p]];
    ReplaceAll[nsmall, Infinity -> "?"] (* Robert Price, Mar 22 2020 *)

Extensions

a(12)-a(18) from Giovanni Resta, Oct 30 2019

A036520 Smallest triangular number containing exactly n 3's.

Original entry on oeis.org

3, 3003, 33153, 3303735, 333336, 333039336, 13333363350, 330335331336, 3033333513330, 303313733373336, 30333330330333465, 313631353332333336, 330332337333331336, 3333043333303433331, 3333333330453337336653, 30733333373333335323321, 330332334339335333331336, 33033333933433336339893330
Offset: 1

Views

Author

Keywords

Crossrefs

Programs

  • Mathematica
    nsmall = Table[Infinity, 20];
    For[i = 0, i <= 10^6, i++, p = PolygonalNumber[i];
      n0 = Count[IntegerDigits[p], 3];
      If[nsmall[[n0]] > p, nsmall[[n0]] = p]];
    ReplaceAll[nsmall, Infinity -> "?"] (* Robert Price, Mar 22 2020 *)

Extensions

a(12)-a(18) from Giovanni Resta, Oct 30 2019

A036522 Smallest triangular number containing exactly n 5's.

Original entry on oeis.org

15, 55, 5565, 255255, 12552555, 585555531, 5355555765, 50525595555, 5258558551555, 555595555515, 1551745755555555, 39355555555552515, 552550545955255555, 13555559555595513555, 455557505555605555585, 5555558514557555255755, 555457555855555784555355, 505555585555455555505395
Offset: 1

Views

Author

Keywords

Crossrefs

Programs

  • Mathematica
    nsmall = Table[Infinity, 20];
    For[i = 0, i <= 10^6, i++, p = PolygonalNumber[i];
      n0 = Count[IntegerDigits[p], 5];
      If[nsmall[[n0]] > p, nsmall[[n0]] = p]];
    ReplaceAll[nsmall, Infinity -> "?"] (* Robert Price, Mar 22 2020 *)

Extensions

a(13)-a(18) from Giovanni Resta, Oct 30 2019

A036523 Smallest triangular number containing exactly n 6's.

Original entry on oeis.org

6, 66, 666, 66066, 5666661, 36666766, 646686666, 77666666626, 4666660668676, 66488766666666, 6666063656661696, 6666664664655666, 666416695266666666, 56666136666666763866, 626646696666896766666, 11666966196628666666666, 66666666636866637006666, 2626660686666666671166666
Offset: 1

Views

Author

Keywords

Crossrefs

Programs

  • Mathematica
    nsmall = Table[Infinity, 20];
    For[i = 0, i <= 10^6, i++, p = PolygonalNumber[i];
      n0 = Count[IntegerDigits[p], 6];
      If[nsmall[[n0]] > p, nsmall[[n0]] = p]];
    ReplaceAll[nsmall, Infinity -> "?"] (* Robert Price, Mar 22 2020 *)

Extensions

a(13)-a(18) from Giovanni Resta, Oct 30 2019

A036524 Smallest triangular number containing exactly n 7's.

Original entry on oeis.org

78, 1770, 72771, 6787770, 37779778, 2476777771, 7477727778, 7077757275771, 27778877747778, 177775772774775, 7777755777787716, 172777077787777785, 7987777777779277726, 177577777275777787371, 377679777777377717778, 77773137747757777775775, 777367777737777774977796, 67775787670776777773777778
Offset: 1

Views

Author

Keywords

Crossrefs

Programs

  • Mathematica
    nsmall = Table[Infinity, 20];
    For[i = 0, i <= 10^6, i++, p = PolygonalNumber[i];
      n0 = Count[IntegerDigits[p], 7];
      If[nsmall[[n0]] > p, nsmall[[n0]] = p]];
    ReplaceAll[nsmall, Infinity -> "?"] (* Robert Price, Mar 22 2020 *)

Extensions

a(13)-a(18) from Giovanni Resta, Oct 30 2019
Showing 1-9 of 9 results.