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.

A048357 a(n) is the index of the smallest triangular number containing exactly n 2's.

Original entry on oeis.org

6, 49, 215, 651, 6651, 66367, 206020, 635959, 6651759, 21411348, 66651759, 666816649, 666651759, 6666651759, 64687340681, 210818509825, 1115546688777, 6666665142651, 21411315850840, 66642647340651, 494412868404984, 2108185106684051, 21083748539063076, 209872546190692806, 494534695369742950
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], 2];
      If[nsmall[[n0]] > i, nsmall[[n0]] = i]];
    ReplaceAll[nsmall, Infinity -> "?"] (* Robert Price, Mar 22 2020 *)

Extensions

a(14)-a(15) from Lars Blomberg, May 13 2011
a(16)-a(18) from Giovanni Resta, Oct 30 2019
a(19)-a(25) from Max Alekseyev, Mar 07 2025

A048358 a(n) is the index of the smallest triangular number containing exactly n 3's.

Original entry on oeis.org

2, 77, 257, 2570, 816, 25808, 163299, 812816, 2463060, 24629808, 246306030, 791999183, 812812816, 2581876578, 81649658057, 247924719918, 812812812816, 8128140492564, 25819877355763, 81708543315045, 816129320553227, 2581981926944235, 8164822512869870, 16329935292787435, 258071204644507494
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], 3];
      If[nsmall[[n0]] > i, nsmall[[n0]] = i]];
    ReplaceAll[nsmall, Infinity -> "?"] (* Robert Price, Mar 22 2020 *)

Extensions

a(12) corrected by Lars Blomberg, May 13 2011
a(13)-a(15) from Lars Blomberg, May 13 2011
a(16)-a(18) from Giovanni Resta, Oct 30 2019
a(19)-a(25) from Max Alekseyev, Mar 07 2025

A048359 a(n) is the index of the smallest triangular number containing exactly n 4's.

Original entry on oeis.org

9, 94, 537, 1043, 29238, 28790, 94238, 942703, 2967970, 45748113, 170565790, 939618480, 2981759361, 29814031731, 94285146809, 298802358238, 2837045748113, 9428516473384, 29810549959517, 537482082424790, 699205897721757, 2974721655733337, 29032426496744790, 29814339990932029, 1043498506508221519
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], 4];
      If[nsmall[[n0]] > i, nsmall[[n0]] = i]];
    ReplaceAll[nsmall, Infinity -> "?"] (* Robert Price, Mar 22 2020 *)

Extensions

a(13)-a(14) from Lars Blomberg, May 13 2011
a(15)-a(18) from Giovanni Resta, Oct 30 2019
a(19)-a(25) from Max Alekseyev, Mar 07 2025

A048360 a(n) is the index of the smallest triangular number containing exactly n 5's.

Original entry on oeis.org

5, 10, 105, 714, 5010, 34221, 103494, 317885, 3243010, 1054130, 55708989, 280555005, 1051237885, 5206833885, 30184681729, 105409283410, 1053999578610, 1005540238434, 8894447217885, 178132285431643, 717642746162114, 3273082806882696, 10445626412576275, 33332433321191885, 105428230332824189
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], 5];
      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

A048361 a(n) is the index of the smallest triangular number containing exactly n 6's.

Original entry on oeis.org

3, 11, 36, 363, 3366, 8563, 35963, 394123, 3055048, 11531588, 115464831, 115470036, 1154484036, 10645763163, 35401884036, 152754484036, 365148371588, 2292012515963, 33065591380305, 115470003521836, 642442319075676, 1154701378423588, 10996978373724908, 36347397889274188, 230810167309875091
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], 6];
      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

A048362 a(n) is the index of the smallest triangular number containing exactly n 7's.

Original entry on oeis.org

12, 59, 381, 3684, 8692, 70381, 122292, 3762381, 7453707, 18856074, 124721736, 587838545, 3996943276, 18845571218, 27483805332, 394393554074, 1246890354231, 11642661866667, 88292437929618, 184774336842416, 1158255177391940, 5962836170393707, 37870196138329618, 59623111421253050, 107479087154457892
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], 7];
      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

A048363 a(n) is the index of the smallest triangular number containing exactly n 8's.

Original entry on oeis.org

7, 87, 312, 1287, 10572, 81103, 397212, 881912, 5270652, 7601169, 134021535, 421518419, 1402775027, 4204494972, 42305694389, 397212509427, 1943649189427, 6130065071251, 76024844477168, 98844816642745, 1333325833012312, 6069248534849827, 13303299356842428, 191199837283345112, 1084811955030810572
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], 8];
      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

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

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
Showing 1-9 of 9 results.