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

Terms

a(0) =0a(1) =1a(2) =6a(3) =33a(4) =280a(5) =3145a(6) =46956a(7) =823585a(8) =16781472a(9) =387422001a(10) =10000100440a(11) =285311670721