# A007756 (b-file synthesized from sequence entry)
1 0
2 0
3 1
4 1
5 2
6 3
7 11
8 38
9 156
10 638
11 2973
12 13882
13 67868
14 338147
15 1720303
16 8905996
17 46774728
18 248918004
19 1340083514
20 7288922610
21 40019870539
22 221582395052
23 1236358849827