O.g.f.: Sum_{n>=0} n^n*(n+3)^n * exp(-n*(n+3)*x) * x^n / n!.

A222077

O.g.f.: Sum_{n>=0} n^n*(n+3)^n * exp(-n*(n+3)*x) * x^n / n!.

Terms

    a(0) =1a(1) =4a(2) =34a(3) =504a(4) =10572a(5) =285408a(6) =9419440a(7) =367571200a(8) =16562241744a(9) =846509123520

External references