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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | -1 |
| 2 | 2 |
| 3 | -6 |
| 4 | 22 |
| 5 | -90 |
| 6 | 394 |
| 7 | -1806 |
| 8 | 8558 |
| 9 | -41586 |
| 10 | 206098 |
| 11 | -1037718 |
| 12 | 5293446 |
| 13 | -27297738 |
| 14 | 142078746 |
| 15 | -745387038 |
| 16 | 3937603038 |
| 17 | -20927156706 |
| 18 | 111818026018 |
| 19 | -600318853926 |
| 20 | 3236724317174 |
| 21 | -17518619320890 |
| 22 | 95149655201962 |
| 23 | -518431875418926 |
| 24 | 2832923350929742 |
| 25 | -15521467648875090 |
[1,-1,2,-6,22,-90,394,-1806,8558,-41586,206098, -1037718,5293446,-27297738,142078746,-745387038, 3937603038,-20927156706,111818026018, -600318853926,3236724317174,-17518619320890, 95149655201962,-518431875418926,2832923350929742, -15521467648875090] |