# A003018 (b-file synthesized from sequence entry)
1 1
2 1
3 2
4 4
5 9
6 20
7 47
8 111
9 270
10 664
11 1659
12 4184
13 10662
14 27367
15 70747
16 183925
17 480656
18 1261630
19 3324772
20 8792592
21 23327249
22 62067785
23 165586565