# A083484 (b-file synthesized from sequence entry)
1 1
2 4
3 12
4 60
5 420
6 2520
7 27720
8 720720
9 720720
10 24504480
11 465585120
12 2793510720
13 64250746560
14 642507465600
15 1927522396800
16 111796299014400
17 3465685269446400
18 20794111616678400
19 727793906583744000