n | a(n) |
---|---|
2 | 1 |
3 | 4 |
4 | 21 |
5 | 130 |
6 | 930 |
7 | 7560 |
8 | 68880 |
9 | 695520 |
10 | 7711200 |
11 | 93139200 |
12 | 1217462400 |
13 | 17124307200 |
14 | 257902444800 |
15 | 4140968832000 |
16 | 70614415872000 |
17 | 1274546617344000 |
18 | 24275666967552000 |
19 | 486580401635328000 |
20 | 10238462617743360000 |
21 | 225651661258383360000 |
22 | 5198503365971435520000 |
[1,4,21,130,930,7560,68880,695520,7711200, 93139200,1217462400,17124307200,257902444800, 4140968832000,70614415872000,1274546617344000, 24275666967552000,486580401635328000, 10238462617743360000,225651661258383360000, 5198503365971435520000] |