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 1-2 of 2 results.

A321285 Expansion of Product_{1 <= i < j} 1/(1 - x^(i*j)).

Original entry on oeis.org

1, 0, 1, 1, 2, 2, 5, 4, 9, 9, 16, 17, 31, 31, 52, 59, 89, 101, 154, 172, 254, 294, 412, 483, 675, 782, 1070, 1265, 1686, 1996, 2647, 3121, 4086, 4854, 6252, 7442, 9534, 11306, 14360, 17092, 21489, 25566, 31989, 37981, 47224, 56123, 69283, 82290, 101185, 119930, 146768
Offset: 0

Views

Author

Seiichi Manyama, Nov 02 2018

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 50; CoefficientList[Series[Product[1/(1 - x^k)^Floor[DivisorSigma[0, k]/2], {k, 1, nmax}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Nov 02 2018 *)

Formula

Euler transform of A056924.
G.f.: Product_{k>0} 1/(1 - x^k)^A056924(k).

A321300 Expansion of Product_{1 <= i < j} (1 - x^(i*j)).

Original entry on oeis.org

1, 0, -1, -1, -1, 0, -1, 1, 1, 2, 2, 2, 0, 0, 2, -2, -1, -3, -1, -4, -4, -4, -1, -1, -2, 0, 3, 7, 3, 4, 5, 7, 5, 8, 3, 2, 4, 1, -6, -2, -8, -8, -12, -9, -9, -11, -13, -12, -6, -8, -6, -8, 11, 5, 6, 8, 18, 12, 22, 21, 28, 26, 28, 12, 21, 22, 11, 0, 0, -4, -18, -17, -38
Offset: 0

Views

Author

Seiichi Manyama, Nov 03 2018

Keywords

Crossrefs

Convolution inverse of A321285.

Programs

  • Mathematica
    nmax = 100; CoefficientList[Series[Product[(1 - x^k)^Floor[DivisorSigma[0, k]/2], {k, 1, nmax}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Nov 03 2018 *)

Formula

G.f.: Product_{k>0} (1 - x^k)^A056924(k).
Showing 1-2 of 2 results.