A379329 G.f. A(x) satisfies A(x) = 1/sqrt( (1 - 2*x) * (1 - 2*x*A(x)) ).

1, 2, 6, 22, 92, 420, 2034, 10262, 53330, 283410, 1532698, 8406698, 46650072, 261416000, 1477208374, 8407900890, 48158339716, 277375020772, 1605477915982, 9333727605762, 54478721494436, 319120526072380, 1875410643820166, 11054224586789010, 65334486288626586, 387118590382759994

Offset

0,2

Links

Table of n, a(n) for n=0..25.

Formula

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

Prog

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

Crossrefs

Cf. A379330, A379331.

Sequence in context: A394340 A342292 A303923 * A264868 A342290 A374549

Adjacent sequences: A379326 A379327 A379328 * A379330 A379331 A379332

Keyword

nonn

Author

Seiichi Manyama, Dec 21 2024

Status

approved