a(n) = n! * sum 1/k! where the sum is over all positive integers k that divide n.

A057625

a(n) = n! * sum 1/k! where the sum is over all positive integers k that divide n.

Terms

    a(0) =1a(1) =3a(2) =7a(3) =37a(4) =121a(5) =1201a(6) =5041a(7) =62161a(8) =423361a(9) =5473441a(10) =39916801a(11) =818959681a(12) =6227020801a(13) =130784734081

External references