2817360domain: NAppears in sequencesa(n) = (2*n+1)*(2*n+2)*(2*n+4)*(2*n+5).at n=19A069079Number T(n,k) of endofunctions on [n] with exactly k fixed points, none of which are isolated; triangle T(n,k), n >= 0, 0 <= k <= n/2, read by rows.at n=28A350454