# A295864 (b-file synthesized from sequence entry) 0 1 1 2 2 12 3 120 4 420 5 7560 6 18480 7 480480 8 900900 9 30630600 10 46558512 11 1955457504 12 2498640144 13 124932007200 14 137680171200 15 7985449929600 16 7735904619300 17 510569704873800 18 441233078286000 19 32651247793164000 20 25467973278667920 21 2088373808850769440 22 1484298740174927040