# A163145 (b-file synthesized from sequence entry)
0 1
1 21
2 420
3 8400
4 167790
5 3351600
6 66948210
7 1337288400
8 26712295890
9 533577313500
10 10658190898110
11 212897044846500
12 4252612111884990
13 84945799915397400
14 1696789816099808010
15 33893325895893882600
16 677018172425014524090
17 13523417772619230573300