475780

Appears in sequences

• a(n) = Sum_{k=0..n} C(n,k) * C(3*n+k,k).at n=6A156886
• Square 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=51A387934