n | a(n) |
---|---|
0 | 1 |
1 | 0 |
2 | 0 |
3 | 1 |
4 | 4 |
5 | 20 |
6 | 130 |
7 | 980 |
8 | 8400 |
9 | 80920 |
10 | 865200 |
11 | 10164000 |
12 | 130114600 |
13 | 1802600800 |
14 | 26867640800 |
15 | 428661633400 |
16 | 7288513232000 |
17 | 131558835408000 |
18 | 2512282795422400 |
19 | 50600743739145600 |
20 | 1071998968264224000 |
21 | 23829055696093648000 |
22 | 554524256514356128000 |
[1,0,0,1,4,20,130,980,8400,80920,865200,10164000, 130114600,1802600800,26867640800,428661633400, 7288513232000,131558835408000,2512282795422400, 50600743739145600,1071998968264224000, 23829055696093648000,554524256514356128000] |