n | a(n) |
---|---|
0 | 1 |
1 | 0 |
2 | 2 |
3 | 12 |
4 | 60 |
5 | 320 |
6 | 2040 |
7 | 15568 |
8 | 133648 |
9 | 1230336 |
10 | 11962400 |
11 | 123144384 |
12 | 1349008320 |
13 | 15731096576 |
14 | 194349866880 |
15 | 2527082917120 |
16 | 34392647418112 |
17 | 488243791183872 |
18 | 7216792525799936 |
19 | 110936087161801728 |
20 | 1771199461131500544 |
21 | 29324602146652307456 |
[1,0,2,12,60,320,2040,15568,133648,1230336, 11962400,123144384,1349008320,15731096576, 194349866880,2527082917120,34392647418112, 488243791183872,7216792525799936, 110936087161801728,1771199461131500544, 29324602146652307456] |