# A144345 (b-file synthesized from sequence entry) 0 1 1 6 2 52 3 600 4 8680 5 151200 6 3082240 7 71998080 8 1896294400 9 55601145600 10 1796277683200 11 63397990656000 12 2427084884224000 13 100175046107136000 14 4434284662872064000 15 209554432423784448000 16 10530302071553904640000 17 560682451860226375680000