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

A243227

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

Terms

    a(0) =1a(1) =1a(2) =15a(3) =602a(4) =46620a(5) =5921520a(6) =1118557440a(7) =294293759760

External references