a(n) = n! * Sum_{k=1..n} ( Sum_{d|k} (-1)^(k/d + 1) * d ) /k.
A356390
a(n) = n! * Sum_{k=1..n} ( Sum_{d|k} (-1)^(k/d + 1) * d ) /k.
Terms
- a(0) =1a(1) =3a(2) =17a(3) =74a(4) =514a(5) =3564a(6) =30708a(7) =250704a(8) =2780496a(9) =29982240a(10) =373350240a(11) =4639870080a(12) =67024333440a(13) =988156834560
External references
- oeis: A356390