G.f. A(x) = (1 + x*A(2*x))^2.A135868G.f. A(x) = (1 + x*A(2*x))^2.Terms a(0) =1a(1) =2a(2) =9a(3) =80a(4) =1368a(5) =45344a(6) =2952208a(7) =381005824a(8) =97928967168External referencesoeis: A135868