# A004536 (b-file synthesized from sequence entry)
0 1
1 0
2 240
3 3640
4 23790
5 99456
6 323680
7 895680
8 2139780
9 4528640
10 8971872
11 16946280
12 29822520
13 49365120
14 80003520
15 127221568
16 193388910
17 282616320
18 409634640
19 590913960
20 825575016
21 1115613440