# A002435 (b-file synthesized from sequence entry)
1 0
2 2
3 6
4 28
5 180
6 662
7 7266
8 24568
9 408360
10 1326122
11 30974526
12 98329108
13 3065784540
14 9596075582
15 384653685786
16 1192744081648
17 59724464976720
18 183983154281042
19 11249503075325046
20 34489251602450188