# A375227 (b-file synthesized from sequence entry) 0 1 1 3 2 12 3 66 4 504 5 5040 6 60840 7 839160 8 12882240 9 217607040 10 4018896000 11 80691811200 12 1750850640000 13 40809559190400 14 1016150162227200 15 26898872647046400 16 753882642267955200 17 22291971504503500800 18 693356807039126630400