n | a(n) |
---|---|
0 | 1 |
1 | 0 |
2 | 0 |
3 | 2 |
4 | 0 |
5 | 0 |
6 | 40 |
7 | 450 |
8 | 0 |
9 | 2240 |
10 | 108000 |
11 | 1786050 |
12 | 246400 |
13 | 30888000 |
14 | 1647734400 |
15 | 36567781250 |
16 | 11531520000 |
17 | 1356752592000 |
18 | 85195294912000 |
19 | 2380490964101250 |
20 | 1210714801920000 |
21 | 153377369153840000 |
[1,0,0,2,0,0,40,450,0,2240,108000,1786050,246400, 30888000,1647734400,36567781250,11531520000, 1356752592000,85195294912000,2380490964101250, 1210714801920000,153377369153840000] |