# A012840 (b-file synthesized from sequence entry)
0 1
1 1
2 1
3 6
4 21
5 120
6 765
7 5376
8 46473
9 415104
10 4371225
11 48143744
12 594635613
13 7784817664
14 110691178325
15 1673986906112
16 27018807872657
17 462531126525952
18 8370279766396593
19 159859054841331712