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%I #5 May 13 2012 16:41:25
%S 1,1,4,24,168,1284,10384,87364,756808,6704968,60471040,553334434,
%T 5124366956,47938322744,452349133904,4300336433872,41148686798000,
%U 396000558255084,3830370110005728,37218151946806512,363109794135657408,3555651588908143457,34934228253014629644
%N G.f. satisfies: A(x) = x + A(A(x)^2)^2 where g.f. A(x) = Sum_{n>=1} a(n)*x^(3*n-2).
%F Self-convolution yields A212392.
%e G.f.: A(x) = x + x^4 + 4*x^7 + 24*x^10 + 168*x^13 + 1284*x^16 + 10384*x^19 +...
%e such that
%e A(A(x)^2)^2 = x^4 + 4*x^7 + 24*x^10 + 168*x^13 + 1284*x^16 + 10384*x^19 +...
%e where
%e A(x)^2 = x^2 + 2*x^5 + 9*x^8 + 56*x^11 + 400*x^14 + 3096*x^17 + 25256*x^20 +...+ A212392(n)*x^(3*n-1) +...
%o (PARI) {a(n)=local(A=x+x^4); for(i=1, n, A=x+subst(A^2, x, A^2+O(x^(3*n)))); polcoeff(A, 3*n-2)}
%o for(n=1, 30, print1(a(n), ", "))
%Y Cf. A212392, A212391.
%K nonn
%O 1,3
%A _Paul D. Hanna_, May 13 2012
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