# A328121 (b-file synthesized from sequence entry) 1 1 2 2 3 15 4 192 5 3450 6 79740 7 2252880 8 75227040 9 2898481320 10 126570502800 11 6177380517000 12 333231084648000 13 19687828831070400 14 1264341183311606400 15 87691200344603856000 16 6532556443068591936000 17 520205544912884502672000 18 44098092640676115673632000 19 3964782594938523231457584000