# A365977 (b-file synthesized from sequence entry)
0 1
1 1
2 2
3 6
4 24
5 120
6 840
7 6720
8 60480
9 604800
10 6652800
11 83462400
12 1138233600
13 16746912000
14 264176640000
15 4444771968000
16 80719172352000
17 1556132497920000
18 31722198842880000
19 681437830993920000
20 15378172899747840000
21 366025806545817600000