# A121357 (b-file synthesized from sequence entry)
0 1
1 1
2 2
3 12
4 90
5 546
6 6156
7 81432
8 942012
9 15114780
10 294765336
11 5069224656
12 108842183352
13 2770895886552
14 64609245619920
15 1742542175582496
16 55074355772360976
17 1626315165597840912
18 53331321825434963232