a(n) = Sum_{d|n} (-1)^(n/d+1)*d^d.

A321385

a(n) = Sum_{d|n} (-1)^(n/d+1)*d^d.

Terms

    a(0) =1a(1) =3a(2) =28a(3) =251a(4) =3126a(5) =46632a(6) =823544a(7) =16776955a(8) =387420517a(9) =9999996878a(10) =285311670612

External references