# A353162 (b-file synthesized from sequence entry) 0 1 1 0 2 4 3 18 4 48 5 1320 6 4200 7 115920 8 994560 9 11793600 10 264055680 11 2601244800 12 67761429120 13 1067726499840 14 21513457405440 15 485310649824000 16 9925206939648000 17 254012624170905600 18 6174538264806912000 19 160933619800835481600 20 4458470291543671603200