87402domain: NAppears in sequencesNumber of (n+4) X 10 0..2 matrices with each 5 X 5 subblock idempotent.at n=9A224623Square array T(n,k), n >= 0, k >= 0, read by antidiagonals downwards, where T(n,0) = 0^n and T(n,k) = k * Sum_{r=0..n} binomial(n,r) * binomial(n+3*r+k,n)/(n+3*r+k) for k > 0.at n=60A378237