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.

A370084 Expansion of e.g.f. exp( Sum_{k>=1} (2*k)! * (x/2)^k/k ).

Original entry on oeis.org

1, 1, 7, 199, 15985, 2810401, 916442551, 497173378087, 416055798439009, 508038355486018945, 867346995542879712871, 2001283948891590010467271, 6070787760933663329315253457, 23660956435620796919900079644449
Offset: 0

Views

Author

Seiichi Manyama, Feb 08 2024

Keywords

Crossrefs

Programs

  • PARI
    my(N=20, x='x+O('x^N)); Vec(serlaplace(exp(sum(k=1, N, (2*k)!*(x/2)^k/k))))

Formula

a(0) = 1; a(n) = (n-1)! * Sum_{k=1..n} (2*k)! * a(n-k) / (2^k * (n-k)!).

A370087 Expansion of e.g.f. exp( Sum_{k>=1} (3*k)!/k! * (x/6)^k/k ).

Original entry on oeis.org

1, 1, 11, 591, 95001, 34158801, 23091398451, 26242572454911, 46391926016144241, 120482101765570623201, 439905589366043539453851, 2180755271892747703236167151, 14267395360715456605222995351561, 120323721300147111590970495558478641
Offset: 0

Views

Author

Seiichi Manyama, Feb 08 2024

Keywords

Crossrefs

Programs

  • PARI
    my(N=20, x='x+O('x^N)); Vec(serlaplace(exp(sum(k=1, N, (3*k)!/k!*(x/6)^k/k))))

Formula

a(0) = 1; a(n) = (1/n) * Sum_{k=1..n} (3*k)!/6^k * binomial(n,k) * a(n-k).
Showing 1-2 of 2 results.