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.

A322801 Number of compositions (ordered partitions) of n into centered pentagonal numbers (A005891).

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 2, 3, 4, 5, 6, 7, 9, 12, 16, 21, 28, 36, 46, 59, 76, 98, 128, 167, 217, 281, 363, 468, 605, 784, 1017, 1320, 1712, 2217, 2869, 3713, 4807, 6227, 8070, 10458, 13549, 17549, 22726, 29430, 38117, 49375, 63962, 82859, 107333, 139026, 180071
Offset: 0

Views

Author

Ilya Gutkovskiy, Dec 26 2018

Keywords

Crossrefs

Programs

  • Maple
    h:= proc(n) option remember; `if`(n<0, 0, (t->
          `if`(((t+1)*5*t+2)/2>n, t-1, t))(1+h(n-1)))
        end:
    a:= proc(n) option remember; `if`(n=0, 1,
          add(a(n-((i+1)*5*i+2)/2), i=0..h(n)))
        end:
    seq(a(n), n=0..60);  # Alois P. Heinz, Dec 28 2018
  • Mathematica
    nmax = 50; CoefficientList[Series[1/(1 - Sum[x^(5 k (k + 1)/2 + 1), {k, 0, nmax}]), {x, 0, nmax}], x]

Formula

G.f.: 1/(1 - Sum_{k>=0} x^(5*k*(k+1)/2+1)).

A322802 Number of compositions (ordered partitions) of n into centered hexagonal numbers (A003215).

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 2, 3, 4, 5, 6, 7, 8, 10, 13, 17, 22, 28, 36, 45, 56, 70, 88, 111, 140, 178, 226, 286, 361, 455, 573, 721, 909, 1148, 1451, 1834, 2318, 2928, 3695, 4661, 5880, 7420, 9366, 11826, 14935, 18860, 23812, 30059, 37941, 47888, 60445, 76302, 96327
Offset: 0

Views

Author

Ilya Gutkovskiy, Dec 26 2018

Keywords

Crossrefs

Programs

  • Maple
    h:= proc(n) option remember; `if`(n<0, 0, (t->
          `if`(3*t*(t+1)+1>n, t-1, t))(1+h(n-1)))
        end:
    a:= proc(n) option remember; `if`(n=0, 1,
          add(a(n-(3*i*(i+1)+1)), i=0..h(n)))
        end:
    seq(a(n), n=0..60);  # Alois P. Heinz, Dec 28 2018
  • Mathematica
    nmax = 53; CoefficientList[Series[1/(1 - Sum[x^(3 k (k + 1) + 1), {k, 0, nmax}]), {x, 0, nmax}], x]

Formula

G.f.: 1/(1 - Sum_{k>=0} x^(3*k*(k+1)+1)).

A322803 Number of compositions (ordered partitions) of n into centered heptagonal numbers (A069099).

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 14, 18, 23, 29, 36, 45, 55, 67, 82, 101, 125, 155, 192, 239, 297, 368, 455, 562, 694, 857, 1058, 1308, 1619, 2005, 2483, 3074, 3805, 4708, 5822, 7198, 8900, 11007, 13616, 16846, 20845, 25795, 31918, 39489
Offset: 0

Views

Author

Ilya Gutkovskiy, Dec 26 2018

Keywords

Crossrefs

Programs

  • Maple
    h:= proc(n) option remember; `if`(n<1, 0, (t->
          `if`((7*(t-1)*t+2)/2>n, t-1, t))(1+h(n-1)))
        end:
    a:= proc(n) option remember; `if`(n=0, 1,
          add(a(n-(7*(i-1)*i+2)/2), i=1..h(n)))
        end:
    seq(a(n), n=0..60);  # Alois P. Heinz, Dec 28 2018
  • Mathematica
    nmax = 54; CoefficientList[Series[1/(1 - Sum[x^(7 k (k + 1)/2 + 1), {k, 0, nmax}]), {x, 0, nmax}], x]

Formula

G.f.: 1/(1 - Sum_{k>=0} x^(7*k*(k+1)/2+1)).

A322856 Number of compositions (ordered partitions) of n into octagonal pyramidal numbers (A002414).

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 19, 24, 30, 37, 45, 54, 64, 76, 91, 110, 135, 166, 204, 250, 305, 370, 447, 539, 650, 787, 956, 1164, 1419, 1730, 2107, 2562, 3110, 3770, 4569, 5540, 6723, 8166, 9926, 12070, 14677, 17841, 21675
Offset: 0

Views

Author

Ilya Gutkovskiy, Dec 29 2018

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 56; CoefficientList[Series[1/(1 - Sum[x^(k (k + 1) (2 k - 1)/2), {k, 1, nmax}]), {x, 0, nmax}], x]

Formula

G.f.: 1/(1 - Sum_{k>=1} x^(k*(k+1)*(2*k-1)/2)).

A331918 Number of compositions (ordered partitions) of n into distinct odd squares.

Original entry on oeis.org

1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 0, 0, 0, 0, 0, 0, 0, 2, 6, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 0, 0, 0, 0, 0, 0, 0, 2, 6, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 6, 0, 0, 0, 0, 0, 1, 2, 6, 24, 0, 0, 0, 0, 0, 2
Offset: 0

Views

Author

Ilya Gutkovskiy, Feb 01 2020

Keywords

Examples

			a(35) = 6 because we have [25, 9, 1], [25, 1, 9], [9, 25, 1], [9, 1, 25], [1, 25, 9] and [1, 9, 25].
		

Crossrefs

Programs

  • Maple
    N:= 200: # for a(0)..a(N)
    G:= mul(1+t*x^(i^2),i=1..floor(sqrt(N)),2):
    F:= proc(n) local R, k, v;
      R:= coeff(G,x,n);
      add(k!*coeff(R,t,k),k=1..degree(R,t))
    end proc:
    F(0):= 1:
    map(F, [$0..N]); # Robert Israel, Feb 03 2020
Showing 1-5 of 5 results.