# A230056 (b-file synthesized from sequence entry) 0 1 1 4 2 9 3 30 4 132 5 720 6 4680 7 35280 8 302400 9 2903040 10 30844800 11 359251200 12 4550515200 13 62270208000 14 915372057600 15 14384418048000 16 240612083712000 17 4268249137152000 18 80029671321600000 19 1581386305314816000 20 32844177110384640000 21 715273190403932160000 22 16298010552775311360000