A366590 G.f. A(x) satisfies A(x) = 1 + x^2*(1+x)^2*A(x)^3.

1, 0, 1, 2, 4, 12, 30, 84, 238, 680, 1993, 5882, 17575, 52976, 160870, 491924, 1512940, 4677672, 14529744, 45320640, 141897039, 445792908, 1404899598, 4440113940, 14069493813, 44689897200, 142268117566, 453839997836, 1450547245960, 4644492976232, 14896047099592

Offset

0,4

Links

Table of n, a(n) for n=0..30.

Formula

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

Prog

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

Crossrefs

Cf. A366221, A366591, A366592.

Cf. A019497.

Sequence in context: A355384 A059412 A079472 * A308556 A148186 A006948

Adjacent sequences: A366587 A366588 A366589 * A366591 A366592 A366593

Keyword

nonn

Author

Seiichi Manyama, Oct 14 2023

Status

approved