# A138315 (b-file synthesized from sequence entry)
0 1
1 1
2 1
3 3
4 9
5 45
6 225
7 3015
8 22545
9 473625
10 4637025
11 191508075
12 2288273625
13 123786785925
14 1735168572225
15 276775700288175
16 4433024011291425
17 510439906229029425
18 9196849128341801025
19 3123191121957643317075