# A318495 (b-file synthesized from sequence entry) 0 1 1 10 2 120 3 1540 4 20500 5 279480 6 3876600 7 54496200 8 774468900 9 11107261000 10 160553895040 11 2336799457200 12 34219387524400 13 503846306168800 14 7455357525594000 15 110811908027490960 16 1653792126235140900 17 24774309852363829800 18 372404448149589213600