A366456 G.f. A(x) satisfies A(x) = 1 + x + x/A(x)^(7/2).

1, 2, -7, 56, -532, 5600, -62860, 737324, -8929726, 110811344, -1401640814, 18004922936, -234243536436, 3080152906096, -40870739065996, 546563064528906, -7358930622768977, 99672580921800656, -1357142384455626909, 18565841939010374736, -255054402946387767408

Offset

0,2

Links

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

Formula

G.f.: A(x) = 1/B(-x) where B(x) is the g.f. of A366402.

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

Prog

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

Crossrefs

Cf. A112478, A364393, A364407, A364408, A364409, A366266, A366267, A366268, A366452, A366453, A366454, A366455.

Cf. A366402.

Sequence in context: A227381 A182055 A358944 * A211209 A363205 A271440

Adjacent sequences: A366453 A366454 A366455 * A366457 A366458 A366459

Keyword

sign

Author

Seiichi Manyama, Oct 10 2023

Status

approved