a(n) = Sum_{k=0..n} stirling1(n,k)*stirling1(n+1,k+1)*k!.

A192558

a(n) = Sum_{k=0..n} stirling1(n,k)*stirling1(n+1,k+1)*k!.

Terms

    a(0) =1a(1) =1a(2) =5a(3) =64a(4) =1454a(5) =50646a(6) =2489402a(7) =163460592a(8) =13786580376

External references