# A001997 (b-file synthesized from sequence entry)
0 1
1 1
2 2
3 4
4 10
5 24
6 66
7 176
8 493
9 1362
10 3821
11 10660
12 29864
13 83329
14 232702
15 648182
16 1804901
17 5015725
18 13931755
19 38635673
20 107090666
21 296449133
22 820271143
23 2267225157
24 6264244414
25 17291930470