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

A168480

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

Terms

    a(0) =1a(1) =2a(2) =20a(3) =640a(4) =78080a(5) =37847040a(6) =74189111296

External references