# A365284 (b-file synthesized from sequence entry)
0 1
1 1
2 2
3 12
4 144
5 1980
6 31680
7 630840
8 15093120
9 411883920
10 12607660800
11 430740858240
12 16265744732160
13 671629503504960
14 30093198326231040
15 1454898560062147200
16 75503612563771392000
17 4186035286381024876800
18 246916968958719605145600