a(n) = (1/n^2) * Sum_{k>=1} k^n * (1 - 1/n)^(k - 1).

A331345

a(n) = (1/n^2) * Sum_{k>=1} k^n * (1 - 1/n)^(k - 1).

Terms

    a(0) =1a(1) =3a(2) =37a(3) =1015a(4) =48601a(5) =3583811a(6) =376372333a(7) =53343571695

External references