A366326 G.f. satisfies A(x) = (1 + x) * (1 + x/A(x)^2).

1, 2, -3, 14, -78, 479, -3131, 21372, -150588, 1087057, -7998295, 59763129, -452257495, 3459109408, -26697940390, 207672518808, -1626400971710, 12813379464399, -101482102525511, 807524595076284, -6452856224076654, 51760509258982478, -416620859045829372

Offset: 0

Author

Seiichi Manyama, Oct 07 2023

Keywords

• sign

Links

• Winston de Greef, Table of n, a(n) for n = 0..1067

Crossrefs

Cf. A073157, A364336, A364337, A364338, A364339, A366325, A366327, A366328.

Cf. A006013, A364393.

Programs

PARI

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

Formula

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