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A135869
G.f. A(x) = 1 + x*A(3x)^2.
1
1, 1, 6, 117, 6642, 1097874, 537135948, 784812995973, 3435153688724346, 45086429284345043334, 1775007791598340247784372, 209630197234751724563143145346, 74271350069687203431923556331222068
OFFSET
0,3
COMMENTS
Self-convolution equals A135870.
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, n)}
CROSSREFS
Sequence in context: A300733 A332627 A100070 * A218713 A360426 A054957
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Dec 02 2007
STATUS
approved