# A006523 (b-file synthesized from sequence entry)
1 2
2 240
3 725760
4 12454041600
5 711374856192000
6 102181884343418880000
7 31022420086661971968000000
8 17683523987479403909087232000000
9 17366635237623772991036388802560000000
10 27527506182452690092631959163161804800000000