# A365976 (b-file synthesized from sequence entry)
0 1
1 1
2 2
3 6
4 24
5 144
6 1008
7 8064
8 72576
9 766080
10 8934912
11 113895936
12 1573254144
13 23864924160
14 389247344640
15 6786673496064
16 125855767166976
17 2492616008171520
18 52243870155079680
19 1154797100239749120
20 26835102086208159744
21 656159502089355264000