# A002168 (b-file synthesized from sequence entry) 0 1 1 8 2 96 3 1664 4 36800 5 1008768 6 32626560 7 1221399040 8 51734584320 9 2459086364672 10 129082499311616 11 7432690738003968 12 464885622793134080 13 31456185663820136448 14 2284815238218471260160 15 177611252880786297913344