# A323019 (b-file synthesized from sequence entry) 0 1 1 2 2 4 3 8 4 20 5 40 6 120 7 520 8 1560 9 8840 10 26520 11 185640 12 769080 13 5383560 14 28455960 15 199191720 16 1166694360 17 8166860520 18 61834801080 19 432843607560 20 3771922865880 21 26403460061160 22 275350369209240 23 1927452584464680 24 21201978429111480 25 171543280017356520