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

Author

Seiichi Manyama, May 29 2023

Keywords

• nonn
• easy

Crossrefs

Cf. A219534, A346626, A363311.

Cf. A217360, A260332, A363304.

Programs

PARI

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

Formula

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