16873930domain: NAppears in sequencesArray read by antidiagonals: T(n,m) is the number of matchings in the rook graph K_n X K_m.at n=31A270227Array read by antidiagonals: T(n,m) is the number of matchings in the rook graph K_n X K_m.at n=32A270227Number of matchings in the 4 X n rook graph.at n=5A341503