# A001573 (b-file synthesized from sequence entry)
1 1
2 2
3 4
4 9
5 23
6 63
7 177
8 514
9 1527
10 4625
11 14230
12 44357
13 139779
14 444558
15 1425151
16 4600339
17 14939849
18 48778197
19 160019885
20 527200711