a(n) = n! * Sum_{k=1..n} ( Sum_{d|k} (-1)^(k/d + 1) ) /k.
A356389
a(n) = n! * Sum_{k=1..n} ( Sum_{d|k} (-1)^(k/d + 1) ) /k.
Terms
- a(0) =1a(1) =2a(2) =10a(3) =34a(4) =218a(5) =1308a(6) =10596a(7) =74688a(8) =793152a(9) =7931520a(10) =94504320a(11) =1054218240a(12) =14662840320a(13) =205279764480
External references
- oeis: A356389