a(n) = Sum_{k=0..n} C(n+k-1,k)*k!.

A123680

a(n) = Sum_{k=0..n} C(n+k-1,k)*k!.

Terms

    a(0) =1a(1) =2a(2) =9a(3) =76a(4) =985a(5) =17046a(6) =366289a(7) =9374968a(8) =278095761a(9) =9375293170a(10) =353906211241

External references