a(n) = (n+2)! * Sum_{k = 1..n} 1/((k+1)*(k+2)).
A180119
a(n) = (n+2)! * Sum_{k = 1..n} 1/((k+1)*(k+2)).
Terms
- a(0) =0a(1) =1a(2) =6a(3) =36a(4) =240a(5) =1800a(6) =15120a(7) =141120a(8) =1451520a(9) =16329600a(10) =199584000a(11) =2634508800a(12) =37362124800a(13) =566658892800
External references
- oeis: A180119