a(n) = n! * Sum_{d|n} d^d / (n/d)!.

A354900

a(n) = n! * Sum_{d|n} d^d / (n/d)!.

Terms

    a(0) =1a(1) =9a(2) =163a(3) =6193a(4) =375001a(5) =33602521a(6) =4150656721a(7) =676462516801

External references