O.g.f.: Sum_{n>=0} n!^2 * x^n / Product_{k=1..n} (1 + k*(n-k+1)*x).
A221094
O.g.f.: Sum_{n>=0} n!^2 * x^n / Product_{k=1..n} (1 + k*(n-k+1)*x).
Terms
- a(0) =1a(1) =1a(2) =3a(3) =21a(4) =263a(5) =5165a(6) =146335a(7) =5649397a(8) =285069735a(9) =18214525629
External references
- oeis: A221094