a(n) = (n!)^2 * Sum_{d|n} (-1)^(d+1) / (d!)^2.
A336242
a(n) = (n!)^2 * Sum_{d|n} (-1)^(d+1) / (d!)^2.
Terms
- a(0) =1a(1) =3a(2) =37a(3) =431a(4) =14401a(5) =403199a(6) =25401601a(7) =1216454399a(8) =135339724801
External references
- oeis: A336242
A336242
a(n) = (n!)^2 * Sum_{d|n} (-1)^(d+1) / (d!)^2.