A135868 - OEIS

%I #4 Dec 24 2012 20:49:00

%S 1,2,9,80,1368,45344,2952208,381005824,97928967168,50238812700672,

%T 51495089926791168,105513593089512439808,432289346894817079853056,

%U 3541746937174189008054386688,58031524865557213409213540204544

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

%C Self-convolution of A135867 such that A135867(n+1) = 2^n*a(n).

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

%Y Cf. A135867.

%K nonn

%O 0,2

%A _Paul D. Hanna_, Dec 02 2007