# A155640 (b-file synthesized from sequence entry)
0 1
1 3
2 25
3 219
4 1777
5 13683
6 102025
7 745419
8 5374177
9 38400483
10 272709625
11 1928498619
12 13597146577
13 95668307283
14 672119557225
15 4717043931819
16 33080342678977
17 231867574534083
18 1624598900644825
19 11379821699045019
20 79696898865971377
21 558069026925080883