A385983 - OEIS

A385983

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

1, 1, 4, 46, 1432, 123808, 30876832, 22731703408, 49898049707776, 327831911519538304, 6455998409280026369536, 381291302353791118798096384, 67549186687935750257213597283328, 35899285521583612190120694413539704832, 57235559192922896714567337515980987820597248

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OFFSET

0,3

LINKS

Table of n, a(n) for n=0..14.

FORMULA

E.g.f. A(x) satisfies A'(x) = A(x) * A(3*x).

PROG

(PARI) a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=sum(j=0, i-1, 3^j*binomial(i-1, j)*v[j+1]*v[i-j])); v;

CROSSREFS

Cf. A000142, A126444, A155585, A385984.

Sequence in context: A210855 A324228 A002077 * A113096 A135078 A195243