A376636 G.f. satisfies A(x) = (1 + 9*x*A(x)^2)^(1/3).

1, 3, 9, 18, 0, -162, -567, 0, 8019, 31590, 0, -520506, -2160756, 0, 38480265, 164549880, 0, -3072083274, -13390246485, 0, 258054995016, 1139882486490, 0, -22474826957232, -100257845970825, 0, 2011064804461548, 9039247392729582, 0, -183769714890451800

Offset

0,2

Links

Table of n, a(n) for n=0..29.

Formula

a(n) = 9^n * binomial(2*n/3 + 1/3,n)/(2*n+1).

Prog

(PARI) a(n) = 9^n*binomial(2*n/3+1/3, n)/(2*n+1);

Crossrefs

Cf. A004987, A008931, A078532, A245114, A376282.

Sequence in context: A009216 A103072 A109228 * A355636 A103162 A310331

Adjacent sequences: A376633 A376634 A376635 * A376637 A376638 A376639

Keyword

sign

Author

Seiichi Manyama, Oct 23 2024

Status

approved