n | a(n) |
---|---|
1 | 1 |
2 | 1 |
3 | 1 |
4 | 3 |
5 | 8 |
6 | 40 |
7 | 180 |
8 | 1260 |
9 | 8064 |
10 | 72576 |
11 | 604800 |
12 | 6652800 |
13 | 68428800 |
14 | 889574400 |
15 | 10897286400 |
16 | 163459296000 |
17 | 2324754432000 |
18 | 39520825344000 |
19 | 640237370572800 |
20 | 12164510040883200 |
21 | 221172909834240000 |
22 | 4644631106519040000 |
23 | 93666727314800640000 |
[1,1,1,3,8,40,180,1260,8064,72576,604800,6652800, 68428800,889574400,10897286400,163459296000, 2324754432000,39520825344000,640237370572800, 12164510040883200,221172909834240000, 4644631106519040000,93666727314800640000] |