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A171200 G.f. satisfies: A(x) = 1 + x*A(2x)^3. 11

%I

%S 1,1,6,84,2312,121056,12173568,2391143424,928316362752,

%T 716762538541056,1103851068987015168,3395472896229407981568,

%U 20875407961847891162038272,256600638160251032545689337856,6307244441266548036155317187248128

%N G.f. satisfies: A(x) = 1 + x*A(2x)^3.

%F a(0) = 1; a(n) = 2^(n-1) * Sum_{i=0..n-1} Sum_{j=0..n-i-1} a(i) * a(j) * a(n-i-j-1). - _Ilya Gutkovskiy_, Nov 03 2021

%t m = 15; A[_] = 0; Do[A[x_] = 1 + x A[2x]^3 + O[x]^m // Normal, {m}];

%t CoefficientList[A[x], x] (* _Jean-Fran├žois Alcover_, Nov 07 2019 *)

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

%Y Cf. A135867, A171201, A171202-A171211.

%K nonn

%O 0,3

%A _Paul D. Hanna_, Dec 05 2009

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Last modified February 5 08:15 EST 2023. Contains 360082 sequences. (Running on oeis4.)