a(n) = exp(-1) * (n+1)! * Sum_{i>j>=0} j^n/i!.

A102244

a(n) = exp(-1) * (n+1)! * Sum_{i>j>=0} j^n/i!.

Terms

    a(0) =1a(1) =1a(2) =5a(3) =42a(4) =544a(5) =10020a(6) =246840a(7) =7790160a(8) =305234496a(9) =14493790080a(10) =818125056000

External references