# A218824 (b-file synthesized from sequence entry)
0 1
1 1
2 2
3 9
4 57
5 421
6 3593
7 34557
8 366832
9 4251094
10 53238166
11 714702779
12 10221402872
13 154913725486
14 2477047085038
15 41629752595369
16 732956458329580
17 13480858878123068
18 258362762534442843
19 5148079352377053578
20 106437899659055825010
21 2279307634231962670724