# A005634 (b-file synthesized from sequence entry)
2 0
3 0
4 1
5 4
6 28
7 85
8 630
9 3096
10 23220
11 123952
12 1036080
13 7230828
14 66349440
15 500721252
16 5080269600
17 45925520096
18 508031496000
19 4919774752448
20 59256847036800
21 656763354386032
22 8532986691801600
23 100525956801641104
24 1405335512577427200
25 18431883446961030912