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.

A291679 Main diagonal of A291678.

Original entry on oeis.org

1, 1, 1, -2, -11, -24, -8, 141, 573, 1087, -174, -8700, -31328, -52740, 36387, 534198, 1742445, 2540583, -3626189, -33115232, -97968686, -118497822, 301668764, 2060526393, 5526622320, 5165256226, -23033840842, -127995025736, -310560935969, -193716799472
Offset: 0

Views

Author

Seiichi Manyama, Aug 29 2017

Keywords

Crossrefs

Formula

a(n) = [x^n] (1 + x/(1 + x^2/(1 + x^3/(1 + x^4/(1 + x^5/(1 + ...))))))^n, a continued fraction.

A302016 Expansion of 1/(1 - x - x^2/(1 + x^2/(1 + x^3/(1 + x^4/(1 + x^5/(1 + ...)))))), a continued fraction.

Original entry on oeis.org

1, 1, 2, 3, 4, 6, 9, 14, 21, 31, 46, 68, 102, 153, 229, 342, 510, 761, 1136, 1697, 2535, 3786, 5653, 8441, 12605, 18824, 28112, 41981, 62691, 93617, 139800, 208768, 311761, 465564, 695242, 1038226, 1550415, 2315284, 3457489, 5163181, 7710344, 11514102, 17194374, 25676907, 38344147
Offset: 0

Views

Author

Ilya Gutkovskiy, Mar 30 2018

Keywords

Crossrefs

Antidiagonal sums of A291678.

Programs

  • Mathematica
    nmax = 44; CoefficientList[Series[1/(1 - x - x^2/(1 + ContinuedFractionK[x^k, 1, {k, 2, nmax}])), {x, 0, nmax}], x]
    nmax = 44; CoefficientList[Series[1/(1 - x QPochhammer[x^2, x^5] QPochhammer[x^3, x^5]/(QPochhammer[x, x^5] QPochhammer[x^4, x^5])), {x, 0, nmax}], x]

Formula

G.f.: 1/(1 - x*Product_{k>=1} (1 - x^(5*k-2))*(1 - x^(5*k-3))/((1 - x^(5*k-1))*(1 - x^(5*k-4)))).
a(0) = 1; a(n) = Sum_{k=1..n} A003823(k-1)*a(n-k).
a(n) ~ c / r^n, where r = 0.669643458685499460127124120930664114507093547265881... is the root of the equation x*QPochhammer[x^2, x^5]*QPochhammer[x^3, x^5] = QPochhammer[x, x^5]*QPochhammer[x^4, x^5] and c = 0.833333547701931811823757549354805979633827853516233646128015838266... - Vaclav Kotesovec, Jun 08 2019
Showing 1-2 of 2 results.