a(n) = Sum_{0<=j<=n, 0<=k<=n} binomial(n,j)^2 * binomial(n,k)^2 * binomial(n+j,n) * binomial(n+k,n) * binomial(j+k,n).
A220119
a(n) = Sum_{0<=j<=n, 0<=k<=n} binomial(n,j)^2 * binomial(n,k)^2 * binomial(n+j,n) * binomial(n+k,n) * binomial(j+k,n).
Terms
- a(0) =1a(1) =12a(2) =804a(3) =88680a(4) =12386340a(5) =1985320512a(6) =348219006744
External references
- oeis: A220119