# A375773 (b-file synthesized from sequence entry) 0 1 1 0 2 0 3 0 4 0 5 120 6 1800 7 16800 8 126000 9 834120 10 6917400 11 129399600 12 3259080000 13 72252300120 14 1370602233000 15 23218349918400 16 377834084082000 17 6709735404918120 18 147369456297228600 19 3899127761438053200 20 109421543771265852000 21 3002806840023201408120