# A183146 (b-file synthesized from sequence entry)
0 1
1 1
2 4
3 16
4 80
5 407
6 2221
7 12380
8 71196
9 417016
10 2484839
11 15001779
12 91603298
13 564661194
14 3509278042
15 21964437947
16 138330334357
17 875977578584
18 5574225259696
19 35626247068500
20 228592067446715
21 1471959684881231