# A165823 (b-file synthesized from sequence entry) 0 1 1 2 2 6 3 24 4 30 5 1440 6 42 7 120960 8 30 9 7257600 10 66 11 958003200 12 2730 13 5230697472000 14 6 15 62768369664000 16 510 17 64023737057280000