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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | -2 |
| 2 | 0 |
| 3 | -42 |
| 4 | 86 |
| 5 | -1638 |
| 6 | 1428 |
| 7 | -71286 |
| 8 | 218592 |
| 9 | -3941590 |
| 10 | 5374096 |
| 11 | -187901262 |
| 12 | 661408902 |
| 13 | -10769651242 |
| 14 | 18007942140 |
| 15 | -597519823962 |
| 16 | 2262843922694 |
| 17 | -34034727280806 |
| 18 | 65527429637360 |
| 19 | -1858398841872062 |
| 20 | 7543997928104274 |
| 21 | -118580678725935186 |
[1,-2,0,-42,86,-1638,1428,-71286,218592,-3941590, 5374096,-187901262,661408902,-10769651242, 18007942140,-597519823962,2262843922694, -34034727280806,65527429637360,-1858398841872062, 7543997928104274,-118580678725935186] |