# A096632 (b-file synthesized from sequence entry) 2 1 3 2 4 3 5 12 6 20 7 180 8 1260 9 1120 10 9072 11 90720 12 184800 13 29937600 14 389188800 15 13453440 16 8172964800 17 130767436800 18 15247232000 19 100037089152000 20 380140938777600 21 10429106688000 22 1451447220787200 23 159659194286592000