# A215223 (b-file synthesized from sequence entry) 1 4 2 12 3 24 4 72 5 120 6 408 7 840 8 2448 9 5760 10 15960 11 39864 12 108024 13 275184 14 728784 15 1895760 16 4998528 17 13033560 18 34250904 19 89602632 20 235157640 21 615871032