A366239 G.f. A(x) satisfies A(x) = 1 + x + x*(1 + x)^2*A(x)^3.

1, 2, 8, 49, 329, 2401, 18452, 147140, 1206157, 10101011, 86047138, 743288984, 6495476548, 57321239999, 510104531479, 4572492374150, 41247768216331, 374175606700172, 3411195598361653, 31236732721224722, 287182875831208468, 2649838553953071239

Offset

0,2

Links

Table of n, a(n) for n=0..21.

Formula

a(n) = Sum_{k=0..n} binomial(4*k+1,n-k) * binomial(3*k,k)/(2*k+1).

Prog

(PARI) a(n) = sum(k=0, n, binomial(4*k+1, n-k)*binomial(3*k, k)/(2*k+1));

Crossrefs

Cf. A364336, A366240, A366241.

Cf. A366221.

Sequence in context: A279239 A279109 A355667 * A364592 A183070 A032116

Adjacent sequences: A366236 A366237 A366238 * A366240 A366241 A366242

Keyword

nonn

Author

Seiichi Manyama, Oct 05 2023

Status

approved