G.f.: A(x) = Product_{n>=0} (1+a(n)*x^(n+1))^2 = Sum_{n>=0} a(n)*x^n.

A093635

G.f.: A(x) = Product_{n>=0} (1+a(n)*x^(n+1))^2 = Sum_{n>=0} a(n)*x^n.

Terms

    a(0) =1a(1) =2a(2) =5a(3) =18a(4) =64a(5) =258a(6) =1061a(7) =4572a(8) =19809a(9) =88972a(10) =400600a(11) =1844602a(12) =8511540a(13) =39919338a(14) =187389085a(15) =891158688a(16) =4238242129a(17) =20365627200a(18) =97881057229a(19) =474301930632

External references