# A178846 (b-file synthesized from sequence entry)
1 1
2 2
3 6
4 12
5 72
6 336
7 1824
8 13152
9 134880
10 649296
11 8572800
12 102194400
13 1033046880
14 12143232960
15 210042192960
16 2372176649280
17 46447968686400
18 648516678024960