a(n) = n!*((n+1)/2 + 2*Sum_{k=2..n-1}(n-k)/(k+1)).
A344216
a(n) = n!*((n+1)/2 + 2*Sum_{k=2..n-1}(n-k)/(k+1)).
Terms
- a(0) =1a(1) =3a(2) =16a(3) =104a(4) =768a(5) =6336a(6) =57888a(7) =581472a(8) =6379200a(9) =75977280a(10) =977045760a(11) =13499930880a(12) =199537067520
External references
- oeis: A344216