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 1-3 of 3 results.

A327280 Decimal expansion of a constant related to A270913 and A327214.

Original entry on oeis.org

2, 6, 0, 5, 4, 2, 2, 3, 3, 1, 4, 2, 4, 3, 8, 4, 6, 9, 4, 3, 3, 8, 6, 0, 8, 3, 2, 1, 6, 0, 4, 2, 2, 4, 8, 7, 6, 7, 6, 9, 0, 2, 0, 6, 0, 3, 9, 0, 8, 1, 6, 3, 0, 9, 2, 6, 3, 0, 2, 5, 9, 0, 1, 0, 2, 4, 1, 0, 3, 7, 5, 7, 2, 8, 9, 6, 2, 5, 4, 2, 2, 7, 8, 3, 5, 6, 5, 0, 8, 6, 0, 4, 0, 4, 4, 3, 1, 1, 4, 1, 0, 1, 0, 6, 2, 6
Offset: 0

Views

Author

Vaclav Kotesovec, Aug 28 2019

Keywords

Examples

			0.26054223314243846943386083216042248767690206039081630926302590102410375728962...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[1/Sqrt[s*Pi*Derivative[0, 2][QPochhammer][-1, r*s]]/r /. FindRoot[{2*s == QPochhammer[-1, r*s], r*Derivative[0, 1][QPochhammer][-1, r*s] == 2}, {r, 1/2}, {s, 1/2}, WorkingPrecision -> 120], 10, 106][[1]] (* Vaclav Kotesovec, Oct 02 2023 *)

Formula

Equals limit_{n->infinity} A270913(n) * sqrt(n) / A270914^n.

A309986 Convolution of A270913 and A008485.

Original entry on oeis.org

1, 2, 9, 43, 206, 999, 4915, 24372, 121698, 611244, 3085612, 15645347, 79639602, 406809249, 2084567381, 10712007629, 55187254157, 284981396231, 1474729519719, 7646180479889, 39713643612380, 206600871071930, 1076372569004514, 5615363541987786, 29331204404385053
Offset: 0

Views

Author

Vaclav Kotesovec, Aug 26 2019

Keywords

Crossrefs

Programs

  • Mathematica
    A270913[n_] := SeriesCoefficient[Product[(1 + x^k)^n, {k, 1, n}], {x, 0, n}];
    A008485[n_] := SeriesCoefficient[Product[1/(1 - x^k)^n, {k, 1, n}], {x, 0, n}];
    Table[Sum[A008485[k]*A270913[n-k], {k, 0, n}], {n, 0, 20}]

Formula

a(n) ~ c * d^n / sqrt(n), where d = A270915 = 5.352701333486642687... and c = 0.446705640528056029457240607298917821281915554...

A327215 Self-convolution of A008485.

Original entry on oeis.org

1, 2, 11, 54, 279, 1442, 7530, 39474, 207693, 1095522, 5790116, 30650038, 162451560, 861920492, 4577055823, 24323292984, 129338944225, 688128700422, 3662798123481, 19504467792378, 103899170100154, 553642311668244, 2951010332435759, 15733439067954134
Offset: 0

Views

Author

Vaclav Kotesovec, Aug 26 2019

Keywords

Crossrefs

Programs

  • Mathematica
    A008485[n_]:=SeriesCoefficient[Product[1/(1-x^k)^n, {k, 1, n}], {x, 0, n}];
    Table[Sum[A008485[k]*A008485[n-k], {k, 0, n}], {n, 0, 25}]

Formula

a(n) ~ c^2 * Pi * d^n, where d = A270915 = 5.352701333486642687772415814165... and c = A327279 = 0.26801521271073331568695383828... (see A008485).
Showing 1-3 of 3 results.