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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | -1 |
| 6 | 1 |
| 7 | -1 |
| 8 | 3 |
| 9 | -15 |
| 10 | 59 |
| 11 | -189 |
| 12 | 567 |
| 13 | -1863 |
| 14 | 7141 |
| 15 | -29817 |
| 16 | 125919 |
| 17 | -528329 |
| 18 | 2238303 |
| 19 | -9769917 |
| 20 | 44312225 |
| 21 | -208177669 |
| 22 | 1005840685 |
| 23 | -4972561375 |
| 24 | 25105651267 |
| 25 | -129470605611 |
| 26 | 682486916465 |
| 27 | -3678964401327 |
| 28 | 20276967904907 |
| 29 | -114199064797229 |
| 30 | 656666370592173 |
[1,1,1,1,-1,1,-1,3,-15,59,-189,567,-1863,7141, -29817,125919,-528329,2238303,-9769917,44312225, -208177669,1005840685,-4972561375,25105651267, -129470605611,682486916465,-3678964401327, 20276967904907,-114199064797229,656666370592173] |