# A110371 (b-file synthesized from sequence entry) 1 2 2 4 3 20 4 168 5 2016 6 31680 7 617760 8 14414400 9 392071680 10 12189864960 11 426645273600 12 16606346803200 13 711700577280000 14 33307587016704000 15 1690360041097728000 16 92472637542405120000 17 5425061402487767040000 18 339780161524233830400000 19 22629358757513973104640000