A135870 G.f. A(x) = (1 + x*A(3x))^2.

1, 2, 13, 246, 13554, 2210436, 1076561037, 1570714992558, 6871883750090694, 90179738434097457084, 3550105797469080332658354, 419263945026939228053105930844, 148543119421079567735277052592081220

Offset

0,2

Comments

Self-convolution of A135869.

Links

Table of n, a(n) for n=0..12.

Prog

(PARI) {a(n)=local(A=1+x+x*O(x^n)); for(i=0, n, A=1+x*subst(A, x, 3*x)^2); polcoeff(A^2, n)}

Crossrefs

Cf. A135868, A135869.

Sequence in context: A187648 A113098 A365590 * A133067 A276744 A042677

Adjacent sequences: A135867 A135868 A135869 * A135871 A135872 A135873

Keyword

nonn

Author

Paul D. Hanna, Dec 02 2007

Status

approved