# A067455 (b-file synthesized from sequence entry)
0 1
1 1
2 2
3 6
4 24
5 120
6 720
7 5040
8 40320
9 0
10 39916800
11 239500800
12 2075673600
13 21794572800
14 261534873600
15 3487131648000
16 50812489728000
17 800296713216000
18 13516122267648000
19 0
20 25545471085854720000
21 281000181944401920000