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 1-4 of 4 results.

A321437 Expansion of Product_{1 <= i <= j} 1/(1 - x^(i^2 + j^2)).

Original entry on oeis.org

1, 0, 1, 0, 1, 1, 1, 1, 2, 1, 4, 1, 4, 3, 4, 5, 5, 6, 9, 6, 13, 8, 14, 13, 15, 19, 21, 21, 29, 24, 38, 32, 42, 44, 51, 56, 65, 65, 83, 79, 102, 99, 120, 125, 144, 154, 176, 183, 213, 219, 262, 266, 311, 322, 369, 392, 437, 465, 526, 550, 635, 650, 747, 781, 871, 937
Offset: 0

Views

Author

Seiichi Manyama, Nov 09 2018

Keywords

Crossrefs

Convolution inverse of A321436.

Formula

G.f.: Product_{k>0} 1/(1 - x^k)^A025426(k).

A321436 Expansion of Product_{1 <= i <= j} (1 - x^(i^2 + j^2)).

Original entry on oeis.org

1, 0, -1, 0, 0, -1, 0, 1, -1, 0, 0, 0, 1, 0, 0, 1, 0, -2, 1, 1, -2, 1, 2, 0, -1, 0, -1, 0, 2, -2, 1, 1, -4, 0, 3, -1, -1, 3, -2, -1, 0, -4, 5, 2, -3, 2, 3, -5, -3, 6, -3, -1, 0, -2, 1, 1, 0, 2, 7, -7, 0, 7, -9, -2, 4, -3, 2, 6, -9, 2, 12, -12, 1, 9, -11, -3, 7, 0, -1, 5
Offset: 0

Views

Author

Seiichi Manyama, Nov 09 2018

Keywords

Crossrefs

Programs

  • Maple
    N:= 100: # for a(1)..a(N)
    P:= 1:
    for i from 1 to floor(sqrt(N)) do
      for j from i while i^2 + j^2 <= N do
        P:= P * (1 - x^(i^2 + j^2))
    od od:
    S:= series(P,x,N+1):
    seq(coeff(S,x,k),k=0..N): # Robert Israel, Apr 21 2024

Formula

G.f.: Product_{k>0} (1 - x^k)^A025426(k).

A319734 Expansion of Product_{0 < i < j} (1 + x^(i^2 + j^2)).

Original entry on oeis.org

1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 1, 0, 2, 1, 1, 1, 1, 3, 1, 1, 1, 2, 3, 1, 2, 2, 3, 3, 2, 4, 3, 3, 4, 3, 5, 3, 3, 6, 5, 6, 4, 6, 8, 6, 6, 7, 8, 9, 7, 8, 10, 10, 12, 10, 12, 13, 11, 15, 15, 14, 15, 14, 20, 19, 16, 21, 20, 25, 22, 22, 27
Offset: 0

Views

Author

Seiichi Manyama, Nov 09 2018

Keywords

Crossrefs

Formula

G.f.: Product_{k>0} (1 + x^k)^A025441(k).

A321457 Expansion of Product_{1 <= i <= j <= k} (1 + x^(i^2 + j^2 + k^2)).

Original entry on oeis.org

1, 0, 0, 1, 0, 0, 1, 0, 0, 2, 0, 1, 2, 0, 2, 2, 0, 3, 3, 1, 4, 4, 2, 5, 4, 3, 7, 7, 5, 9, 10, 7, 11, 14, 9, 15, 19, 12, 22, 23, 17, 30, 29, 23, 41, 37, 32, 54, 46, 45, 68, 59, 63, 85, 79, 85, 107, 103, 108, 136, 136, 139, 174, 177, 178, 222, 225, 226, 287, 282, 290
Offset: 0

Views

Author

Seiichi Manyama, Nov 10 2018

Keywords

Crossrefs

Formula

G.f.: Product_{k>0} (1 + x^k)^A025427(k).
Showing 1-4 of 4 results.