# A007631 (b-file synthesized from sequence entry)
0 1
1 1
2 0
3 0
4 2
5 4
6 0
7 2
8 10
9 32
10 38
11 140
12 496
13 1186
14 3178
15 16792
16 82038
17 289566
18 1139874
19 5914118
20 33800010
21 142337180
22 721286448
23 4384569864