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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | -9 |
| 2 | 36 |
| 3 | -93 |
| 4 | 207 |
| 5 | -459 |
| 6 | 957 |
| 7 | -1827 |
| 8 | 3357 |
| 9 | -6061 |
| 10 | 10620 |
| 11 | -18045 |
| 12 | 30006 |
| 13 | -49122 |
| 14 | 79128 |
| 15 | -125247 |
| 16 | 195435 |
| 17 | -301599 |
| 18 | 460167 |
| 19 | -694026 |
| 20 | 1036368 |
| 21 | -1534305 |
| 22 | 2252277 |
| 23 | -3278709 |
| 24 | 4736973 |
| 25 | -6797196 |
| 26 | 9689103 |
| 27 | -13722487 |
[1,-9,36,-93,207,-459,957,-1827,3357,-6061,10620, -18045,30006,-49122,79128,-125247,195435,-301599, 460167,-694026,1036368,-1534305,2252277,-3278709, 4736973,-6797196,9689103,-13722487] |