a(n) = Sum_{k=0..n} (-1)^(n-k) C(n,k)*C((k+1)^2, n).
A003236
a(n) = Sum_{k=0..n} (-1)^(n-k) C(n,k)*C((k+1)^2, n).
Terms
- a(0) =1a(1) =3a(2) =24a(3) =320a(4) =6122a(5) =153762a(6) =4794664a(7) =178788528a(8) =7762727196a(9) =384733667780
External references
- oeis: A003236