# A012773 (b-file synthesized from sequence entry)
0 1
1 1
2 1
3 6
4 21
5 100
6 645
7 4256
8 34153
9 302352
10 2966505
11 32245664
12 380114493
13 4879093440
14 67244074989
15 996485811712
16 15717842398417
17 264232448010496
18 4694489063253585
19 88283645811756544
20 1744673430747688805