A171211 - OEIS

%I #8 Nov 07 2019 05:26:09

%S 1,8,156,5944,425286,57811000,15246040860,7918843018760,

%T 8165859019876353,16781575370067304448,68855523432488884833408,

%U 564547878300963670909315840,9253510119618208634494942344960

%N G.f. satisfies: A(x) = (1 + x*A(2x))^8.

%F Self-convolution 8th power of A171210 where a(n) = A171210(n+1)/2^n for n>=0.

%t m = 13; A[_] = 0; Do[A[x_] = (1 + x A[2 x])^8 + O[x]^m // Normal, {m}];

%t CoefficientList[A[x], x] (* _Jean-François 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))^8); polcoeff(A, n)}

%Y Cf. A135868, A171200-A171209, A171210.

%K nonn

%O 0,2

%A _Paul D. Hanna_, Dec 05 2009