a(n) = n! * Sum_{k=0..n} k^(n-k) * (n-k)^k/k!.

A351768

a(n) = n! * Sum_{k=0..n} k^(n-k) * (n-k)^k/k!.

Terms

    a(0) =1a(1) =0a(2) =2a(3) =18a(4) =276a(5) =6260a(6) =190950a(7) =7523082a(8) =371286440a(9) =22356290952

External references