a(n) = sum(stirling2(n+1,k+1)*k!^2,k=0..n).

A192550

a(n) = sum(stirling2(n+1,k+1)*k!^2,k=0..n).

Terms

    a(0) =1a(1) =2a(2) =8a(3) =68a(4) =1052a(5) =25772a(6) =915308a(7) =44417228a(8) =2822059052a(9) =227292363212

External references