A365848 Expansion of (1/x) * Series_Reversion( x*(1-x)^5/(1+x)^4 ).

1, 9, 122, 1965, 34814, 655290, 12861708, 260312853, 5393696150, 113847928558, 2439377254412, 52919446267698, 1160040801590332, 25655668799151700, 571760925292574640, 12827392114274902629, 289470689505615716070, 6566330844138035042982

Offset: 0

Author

Seiichi Manyama, Sep 20 2023

Keywords

• nonn

Crossrefs

Cf. A066357, A365754, A365846, A365847.

Programs

PARI

a(n) = sum(k=0, n, binomial(5*n+k+4, k)*binomial(4*(n+1), n-k))/(n+1);

Formula

a(n) = (1/(n+1)) * Sum_{k=0..n} binomial(5*n+k+4,k) * binomial(4*(n+1),n-k).