# A135920 (b-file synthesized from sequence entry)
0 1
1 1
2 2
3 7
4 37
5 264
6 2433
7 27913
8 386906
9 6346119
10 121159373
11 2655174768
12 66028903633
13 1845579100993
14 57506847262162
15 1983312152411351
16 75238783332550789
17 3122408658986242072
18 141063757638078429489