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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | -2 |
| 3 | 3 |
| 4 | -12 |
| 5 | 73 |
| 6 | -440 |
| 7 | 2779 |
| 8 | -23968 |
| 9 | 260177 |
| 10 | -2866432 |
| 11 | 32853491 |
| 12 | -441968384 |
| 13 | 6787498521 |
| 14 | -108247087104 |
| 15 | 1803655970635 |
| 16 | -33080353591296 |
| 17 | 660549566885793 |
| 18 | -13769854019436544 |
| 19 | 299826162055728355 |
[0,1,-2,3,-12,73,-440,2779,-23968,260177,-2866432, 32853491,-441968384,6787498521,-108247087104, 1803655970635,-33080353591296,660549566885793, -13769854019436544,299826162055728355] |