# A177279 (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 282240
10 1764000
11 10118880
12 54888240
13 289147152
14 1510241892
15 7937250452
16 42396685874
17 228146155304
18 1228995185960
19 6598619633952
20 35220099648960