n | a(n) |
---|---|
0 | 1 |
1 | 1 |
2 | 1 |
3 | 4 |
4 | 22 |
5 | 108 |
6 | 612 |
7 | 4416 |
8 | 36576 |
9 | 331200 |
10 | 3319200 |
11 | 36806400 |
12 | 445046400 |
13 | 5813579520 |
14 | 81716947200 |
15 | 1230656716800 |
16 | 19761225523200 |
17 | 336973967769600 |
18 | 6082189179494400 |
19 | 115851849523200000 |
20 | 2322322137354240000 |
21 | 48869666136023040000 |
[1,1,1,4,22,108,612,4416,36576,331200,3319200, 36806400,445046400,5813579520,81716947200, 1230656716800,19761225523200,336973967769600, 6082189179494400,115851849523200000, 2322322137354240000,48869666136023040000] |