# A227462 (b-file synthesized from sequence entry)
1 1
2 2
3 12
4 144
5 2400
6 50760
7 1310400
8 39984000
9 1407490560
10 56143130400
11 2502730137600
12 123302540148480
13 6653043673436160
14 390182090889951360
15 24713127865269043200
16 1681180295452142284800
17 122252619549518954496000
18 9463442426016057083404800
19 776944497581062575154790400