518320domain: NAppears in sequencesNumber of n X 3 0..2 arrays with no column j greater than column j-1 in all rows.at n=3A212925T(n,k) = number of n X k 0..k-1 arrays with no column j greater than column j-1 in all rows.at n=18A212930Number of 4Xn 0..n-1 arrays with no column j greater than column j-1 in all rows.at n=2A212933