A385699 G.f. A(x) satisfies A(x) = 1/( 1 - x*(A(x) + A(-x))*(A(x) + A(w*x) + A(w^2*x))/6 ), where w = exp(2*Pi*i/3).

1, 1, 1, 2, 5, 13, 24, 88, 181, 523, 1616, 4891, 10540, 42009, 94953, 294102, 957259, 3028320, 6864540, 28208447, 66180997, 211105506, 703497178, 2273009790, 5283518340, 22058432677, 52795736539, 171169636087, 578132050147, 1891182035377, 4462525373212

Offset

0,4

Links

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

Formula

a(0) = 1; a(n) = Sum_{i, j, k>=0 and i+2*j+3*k=n-1} a(i) * a(2*j) * a(3*k).

Crossrefs

Cf. A047749, A124753, A217138, A385698.

Sequence in context: A106009 A194552 A079780 * A178621 A383449 A362105

Adjacent sequences: A385696 A385697 A385698 * A385700 A385701 A385702

Keyword

nonn

Author

Seiichi Manyama, Jul 07 2025

Status

approved