n | a(n) |
---|---|
1 | 1 |
2 | 0 |
3 | 0 |
4 | 2 |
5 | 2 |
6 | 4 |
7 | 28 |
8 | 0 |
9 | 20 |
10 | 20 |
11 | 180 |
12 | 520 |
13 | 1888 |
14 | 6016 |
15 | 22480 |
16 | 105236 |
17 | 433500 |
18 | 1933604 |
19 | 9687268 |
20 | 50998366 |
21 | 269523272 |
22 | 1507984008 |
[1,0,0,2,2,4,28,0,20,20,180,520,1888,6016,22480, 105236,433500,1933604,9687268,50998366,269523272, 1507984008] |