# A016175 (b-file synthesized from sequence entry)
0 1
1 18
2 252
3 3240
4 40176
5 489888
6 5925312
7 71383680
8 858283776
9 10309483008
10 123774262272
11 1485653944320
12 17830024114176
13 213973350064128
14 2567758564933632
15 30813572964188160
16 369765696680165376