A367074 G.f. satisfies A(x) = 1 + 2*x + 2*x^3*A(x)^3.

1, 2, 0, 2, 12, 24, 28, 120, 480, 1056, 2304, 8448, 27760, 69600, 191232, 643104, 1978560, 5470080, 16353792, 52557312, 159694848, 468853760, 1444300800, 4549644288, 13905927936, 42219904512, 131505807360, 411672307200, 1270614647808, 3928681875456

Offset

0,2

Links

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

Formula

a(n) = Sum_{k=0..floor(n/3)} 2^(n-2*k) * binomial(2*k+1,n-3*k) * A001764(k).

Prog

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

Crossrefs

Cf. A001764, A366555, A367072, A367073.

Cf. A367113.

Sequence in context: A122496 A335756 A230813 * A177113 A347010 A281205

Adjacent sequences: A367071 A367072 A367073 * A367075 A367076 A367077

Keyword

nonn

Author

Seiichi Manyama, Nov 05 2023

Status

approved