a(n) = Sum_{k=0..n-1} binomial(n,k)^2 * (n-k-1)!.
A352149
a(n) = Sum_{k=0..n-1} binomial(n,k)^2 * (n-k-1)!.
Terms
- a(0) =0a(1) =1a(2) =5a(3) =20a(4) =90a(5) =499a(6) =3395a(7) =27474a(8) =256984a(9) =2720169a(10) =32080501a(11) =416574212a(12) =5900292266a(13) =90461885331
External references
- oeis: A352149