a(n) = Sum_{k=1..n} binomial(k+1,2) * n^(n-k).

A368534

a(n) = Sum_{k=1..n} binomial(k+1,2) * n^(n-k).

Terms

    a(0) =0a(1) =1a(2) =5a(3) =24a(4) =146a(5) =1215a(6) =13431a(7) =186816a(8) =3130436a(9) =61291125a(10) =1371742105a(11) =34522712136a(12) =964626945558

External references