n | a(n) |
---|---|
1 | 1 |
2 | 1 |
3 | -4 |
4 | 6 |
5 | 24 |
6 | -240 |
7 | 720 |
8 | 5040 |
9 | -80640 |
10 | 362880 |
11 | 3628800 |
12 | -79833600 |
13 | 479001600 |
14 | 6227020800 |
15 | -174356582400 |
16 | 1307674368000 |
17 | 20922789888000 |
18 | -711374856192000 |
19 | 6402373705728000 |
20 | 121645100408832000 |
21 | -4865804016353280000 |
22 | 51090942171709440000 |
[1,1,-4,6,24,-240,720,5040,-80640,362880,3628800, -79833600,479001600,6227020800,-174356582400, 1307674368000,20922789888000,-711374856192000, 6402373705728000,121645100408832000, -4865804016353280000,51090942171709440000] |