A363380 G.f. satisfies A(x) = 1 + x * A(x)^4 * (1 + A(x)^2).

1, 2, 20, 284, 4712, 85392, 1638112, 32699472, 672188768, 14133399744, 302535052160, 6570819330688, 144442463464704, 3207564324825600, 71848240540852224, 1621452789508328704, 36831997860270007808, 841470878382566444032

Offset

0,2

Links

Table of n, a(n) for n=0..17.

Formula

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

Prog

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

Crossrefs

Cf. A219534, A346626, A363311.

Cf. A217360, A260332, A363304.

Sequence in context: A217364 A365771 A326010 * A349963 A246482 A124211

Adjacent sequences: A363377 A363378 A363379 * A363381 A363382 A363383

Keyword

nonn,easy

Author

Seiichi Manyama, May 29 2023

Status

approved