A366327 G.f. satisfies A(x) = (1 + x) * (1 + x/A(x)^3).

1, 2, -5, 33, -260, 2263, -20979, 203124, -2030121, 20786694, -216928144, 2298911699, -24673591005, 267644087524, -2929602893537, 32317666058508, -358931896710948, 4010200327457883, -45040693394259858, 508253687784232108, -5759468659295939684

Offset: 0

Author

Seiichi Manyama, Oct 07 2023

Keywords

• sign

Crossrefs

Cf. A073157, A364336, A364337, A364338, A364339, A366325, A366326, A366328.

Cf. A006632, A364407.

Programs

PARI

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

Formula

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