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 1-5 of 5 results.

A322636 Numbers that are sums of consecutive heptagonal numbers (A000566).

Original entry on oeis.org

0, 1, 7, 8, 18, 25, 26, 34, 52, 55, 59, 60, 81, 89, 107, 112, 114, 115, 136, 148, 170, 188, 189, 193, 195, 196, 235, 248, 260, 282, 286, 300, 307, 308, 337, 341, 342, 396, 403, 424, 430, 448, 449, 455, 456, 469, 521, 530, 540, 572, 585, 616, 619, 628, 637, 644, 645, 684, 697
Offset: 1

Views

Author

Ilya Gutkovskiy, Dec 21 2018

Keywords

Crossrefs

Programs

  • Maple
    N:= 1000: # for terms up to N
    Hepta:= [seq(n*(5*n-3)/2,n=0..floor((3+sqrt(9+40*N))/10))]:
    PS:= ListTools:-PartialSums(Hepta):
    S:= select(`<=`,{0,seq(seq(PS[i]-PS[j],j=1..i-1),i=1..nops(PS))},N):
    sort(convert(S,list)); # Robert Israel, May 22 2025
  • Mathematica
    terms = 59;
    nmax = 17; kmax = 9; (* empirical *)
    T = Table[n(5n-3)/2, {n, 0, nmax}];
    Union[T, Table[k MovingAverage[T, k], {k, 2, kmax}]//Flatten][[1 ;; terms]] (* Jean-François Alcover, Dec 26 2018 *)

A322637 Numbers that are sums of consecutive octagonal numbers (A000567).

Original entry on oeis.org

0, 1, 8, 9, 21, 29, 30, 40, 61, 65, 69, 70, 96, 105, 126, 133, 134, 135, 161, 176, 201, 222, 225, 229, 230, 231, 280, 294, 309, 334, 341, 355, 363, 364, 401, 405, 408, 470, 481, 505, 510, 531, 534, 539, 540, 560, 621, 630, 645, 681, 695, 735, 736, 749, 756, 764, 765, 814, 833, 846
Offset: 1

Views

Author

Ilya Gutkovskiy, Dec 21 2018

Keywords

Crossrefs

Programs

  • Maple
    N:= 1000: # for terms up to N
    Octa:= [seq(n*(3*n-2),n=0..floor((1+sqrt(1+3*N))/3))]:
    PS:= ListTools:-PartialSums(Octa):
    S:= select(`<=`,{0,seq(seq(PS[i]-PS[j],j=1..i-1),i=1..nops(PS))},N):
    sort(convert(S,list)); # Robert Israel, May 22 2025
  • Mathematica
    terms = 60;
    nmax = 17; kmax = 9; (* empirical *)
    T = Table[n(3n-2), {n, 0, nmax}];
    Union[T, Table[k MovingAverage[T, k], {k, 2, kmax}]//Flatten][[1 ;; terms]] (* Jean-François Alcover, Dec 26 2018 *)

A319184 Numbers that are sums of consecutive pentagonal numbers.

Original entry on oeis.org

0, 1, 5, 6, 12, 17, 18, 22, 34, 35, 39, 40, 51, 57, 69, 70, 74, 75, 86, 92, 108, 117, 120, 121, 125, 126, 145, 156, 162, 176, 178, 190, 195, 196, 209, 210, 213, 247, 248, 262, 270, 279, 282, 287, 288, 321, 330, 354, 365, 376, 386, 387, 399, 404, 405, 424, 425, 438, 457, 475
Offset: 1

Views

Author

Ilya Gutkovskiy, Dec 21 2018

Keywords

Crossrefs

Programs

  • Mathematica
    anmax = 1000; nmax = Floor[Sqrt[2*anmax/3]] + 1; Select[Union[Flatten[Table[Sum[k*(3*k-1)/2, {k, i, j}], {i, 0, nmax}, {j, i, nmax}]]], # <= anmax &] (* Vaclav Kotesovec, Dec 21 2018 *)
    Module[{nn=20,pn},pn=PolygonalNumber[5,Range[0,nn]];Take[Union[Flatten[Table[Total/@Partition[pn,d,1],{d,nn}]]],60]] (* Harvey P. Dale, Jun 22 2025 *)

A334010 a(n) is the least integer that can be expressed as the sum of one or more consecutive nonzero hexagonal numbers in exactly n ways.

Original entry on oeis.org

1, 703, 274550, 11132303325
Offset: 1

Views

Author

Ilya Gutkovskiy, Apr 12 2020

Keywords

Examples

			Let S(k, m) denote the sum of m hexagonal numbers starting from the k-th. We have
a(1) = S(1, 1);
a(2) = S(19, 1) = S(13, 2);
a(3) = S(62, 25) = S(184, 4) = S(25, 51);
a(4) = S(3065, 505) = S(22490, 11) = S(1215, 1430) = S(1938, 946).
		

Crossrefs

Extensions

a(4) from Giovanni Resta, Apr 13 2020

A322651 Numbers that are sums of consecutive hexagonal pyramidal numbers (A002412).

Original entry on oeis.org

0, 1, 7, 8, 22, 29, 30, 50, 72, 79, 80, 95, 145, 161, 167, 174, 175, 252, 256, 306, 328, 335, 336, 372, 413, 508, 525, 558, 580, 587, 588, 624, 715, 785, 880, 897, 930, 946, 952, 959, 960, 1149, 1222, 1240, 1310, 1405, 1455, 1477, 1484, 1485, 1547, 1612, 1661, 1864, 1925
Offset: 1

Views

Author

Ilya Gutkovskiy, Dec 21 2018

Keywords

Crossrefs

Showing 1-5 of 5 results.