a(n) = (n - 1)! * sigma_2(n), where sigma_2(n) = sum of squares of divisors of n (A001157).
A318250
a(n) = (n - 1)! * sigma_2(n), where sigma_2(n) = sum of squares of divisors of n (A001157).
Terms
- a(0) =1a(1) =5a(2) =20a(3) =126a(4) =624a(5) =6000a(6) =36000a(7) =428400a(8) =3669120a(9) =47174400a(10) =442713600a(11) =8382528000a(12) =81430272000
External references
- oeis: A318250