# A307363 (b-file synthesized from sequence entry) 0 1 1 1 2 3 3 20 4 218 5 3514 6 77386 7 2220504 8 80085792 9 3533917704 10 186779329704 11 11623513158960 12 839754709300800 13 69603737430736560 14 6552428441847854640 15 694531396130434062720 16 82265733994694038784640 17 10816812417663289139328000 18 1569560370536552329095091200