126386domain: NAppears in sequencesa(n) = Sum_{k=0..n} C(n,k) * C(4*n+k,k).at n=5A156887a(n) = Sum_{k=0..floor(n/3)} binomial(n+2,3*k+2) * Catalan(k).at n=15A360045Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where A(n,k) = Sum_{j=0..n} binomial(n,j) * binomial(k*n+j,j).at n=50A387934