A366406 G.f. A(x) satisfies A(x) = (1 + x / A(x)^(7/2)) / (1 - x).

1, 2, -5, 44, -383, 3782, -39653, 434324, -4910009, 56862170, -671131131, 8043570088, -97629201137, 1197607836678, -14824033357867, 184923041147906, -2322472423266102, 29341825623660226, -372652945642370654, 4755048678561786946, -60929667733382420198

Offset

0,2

Links

Table of n, a(n) for n=0..20.

Formula

a(n) = (-1)^(n-1) * Sum_{k=0..n} binomial(9*k/2-1,k) * binomial(7*k/2-1,n-k) / (9*k/2-1).

Prog

(PARI) a(n) = (-1)^(n-1)*sum(k=0, n, binomial(9*k/2-1, k)*binomial(7*k/2-1, n-k)/(9*k/2-1));

Crossrefs

Cf. A366400, A366401, A366402, A366403, A366404, A366405, A366407.

Sequence in context: A333734 A163115 A221682 * A088309 A334252 A307147

Adjacent sequences: A366403 A366404 A366405 * A366407 A366408 A366409

Keyword

sign

Author

Seiichi Manyama, Oct 09 2023

Status

approved