a(n) = Sum_{k=0..n} (k!)^2 * binomial(k+3,3) * Stirling2(n,k)^2.

A382739

a(n) = Sum_{k=0..n} (k!)^2 * binomial(k+3,3) * Stirling2(n,k)^2.

Terms

    a(0) =1a(1) =4a(2) =44a(3) =1084a(4) =48044a(5) =3281404a(6) =316032044a(7) =40592233084

External references