# A005631 (b-file synthesized from sequence entry)
0 1
1 2
2 6
3 18
4 60
5 200
6 760
7 2888
8 11856
9 48672
10 215904
11 957728
12 4506304
13 21203072
14 105494400
15 524880000
16 2737670400
17 14279148032
18 77836363264
19 424289980928
20 2405307227136
21 13635728197632
22 80188215392256
23 471566299547648
24 2867649768509440
25 17438513317683200