# A372991 (b-file synthesized from sequence entry) 0 1 1 1 2 24 3 30 4 56 5 2160 6 3960 7 10192 8 518400 9 1211760 10 3872960 11 239500800 12 668891520 13 2517424000 14 181062604800 15 581935622400 16 2497284608000 17 203152242585600 18 733238884224000 19 3511182158848000 20 316917498433536000 21 1262637358633728000 22 6643156644540416000