# A101179 (b-file synthesized from sequence entry) 1 1 2 2 3 1 4 24 5 64 6 540 7 8640 8 34560 9 103680 10 3326400 11 23224320 12 96768000 13 764225280 14 24385536000 15 108391219200 16 1097349120000 17 29847896064000 18 347640201216000 19 12239832084480000 20 2008587829248000 21 365022211276800000