92875776domain: NAppears in sequencesTerms satisfy: a(2*n) = a(n)*b(n) and a(2*n+1) = a(n)*b(n+1) for n>=0 with a(0)=1, where A(x)^2 = Sum_{n>=0} b(n)*x^n and g.f. A(x) = Sum_{n>=0} a(n)*x^n.at n=21A257889