a(n) = sum(stirling2(n,k)*(k+1)!*(k+3)!,k=1..n)/48.

A261833

a(n) = sum(stirling2(n,k)*(k+1)!*(k+3)!,k=1..n)/48.

Terms

    a(0) =1a(1) =16a(2) =406a(3) =14866a(4) =740026a(5) =48026266a(6) =3937533706a(7) =397912444666

External references