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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | -3 |
| 5 | -4 |
| 6 | -13 |
| 7 | 23 |
| 8 | 87 |
| 9 | 415 |
| 10 | -152 |
| 11 | -8063 |
| 12 | -38727 |
| 13 | -142471 |
| 14 | 2309453 |
| 15 | 2309453 |
| 16 | 13609844 |
| 17 | 187790979 |
| 18 | -1743980081 |
| 19 | -25547499185 |
| 20 | -575984295329 |
| 21 | 1873521429456 |
| 22 | 217675476797921 |
| 23 | 5045023692031697 |
| 24 | 65853623974941521 |
[0,1,1,1,-3,-4,-13,23,87,415,-152,-8063,-38727, -142471,2309453,2309453,13609844,187790979, -1743980081,-25547499185,-575984295329, 1873521429456,217675476797921,5045023692031697, 65853623974941521] |