# A297204 (b-file synthesized from sequence entry)
0 1
1 1
2 1
3 2
4 6
5 24
6 120
7 719
8 5017
9 39938
10 357100
11 3542771
12 38615127
13 458663713
14 5896341413
15 81562642449
16 1207920218823
17 19068760619088
18 319648589219950
19 5670332828427154
20 106122789165032548
21 2089715042280197113