517194

Appears in sequences

• a(n) = Sum_{k=0..n} binomial(3*k,k)*binomial(3*n-3*k,n-k).at n=7A006256
• Square array T(n,k), n >= 0, k >= 0, read by antidiagonals downwards, where T(n,k) = Sum_{j=0..n} binomial(k*j,j) * binomial(k*(n-j),n-j).at n=62A358050