# A374649 (b-file synthesized from sequence entry) 2 3 3 5 4 18 5 90 6 552 7 3960 8 32400 9 297360 10 3024000 11 33747840 12 410054400 13 5388768000 14 76161254400 15 1151998848000 16 18568976025600 17 317764871424000 18 5753767219200000 19 109907415281664000 20 2208818928476160000 21 46590073456582656000 22 1029117549458718720000