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

A192546

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

Terms

    a(0) =1a(1) =1a(2) =4a(3) =26a(4) =251a(5) =3157a(6) =50310a(7) =978315a(8) =22616102a(9) =610543614a(10) =18953178234a(11) =668200802513

External references