| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | -12 |
| 5 | 60 |
| 6 | -210 |
| 7 | 1260 |
| 8 | -8400 |
| 9 | 54432 |
| 10 | -456360 |
| 11 | 4469520 |
| 12 | -45154296 |
| 13 | 493288224 |
| 14 | -5892938688 |
| 15 | 75085701600 |
| 16 | -1017515316480 |
| 17 | 14668694264704 |
| 18 | -223340767219392 |
| 19 | 3570533188036992 |
| 20 | -59698808359690112 |
| 21 | 1038791996385239040 |
[1,0,0,0,-12,60,-210,1260,-8400,54432,-456360, 4469520,-45154296,493288224,-5892938688, 75085701600,-1017515316480,14668694264704, -223340767219392,3570533188036992, -59698808359690112,1038791996385239040] |