# A163092 (b-file synthesized from sequence entry) 0 1 1 16 2 240 3 3600 4 53880 5 806400 6 12069120 7 180633600 8 2703470280 9 40461750000 10 605574696720 11 9063392310000 12 135648138214680 13 2030190989349600 14 30385049935084320 15 454760790684530400 16 6806221388012959080 17 101865971146974325200 18 1524586916316221551920