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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | -1 |
| 2 | 0 |
| 3 | 1 |
| 4 | 1 |
| 5 | -2 |
| 6 | -9 |
| 7 | -9 |
| 8 | 50 |
| 9 | 267 |
| 10 | 413 |
| 11 | -2180 |
| 12 | -17731 |
| 13 | -50533 |
| 14 | 110176 |
| 15 | 1966797 |
| 16 | 9938669 |
| 17 | 8638718 |
| 18 | -278475061 |
| 19 | -2540956509 |
| 20 | -9816860358 |
| 21 | 27172288399 |
| 22 | 725503033401 |
| 23 | 5592543175252 |
| 24 | 15823587507881 |
| 25 | -168392610536153 |
| 26 | -2848115497132448 |
| 27 | -20819319685262839 |
[1,-1,0,1,1,-2,-9,-9,50,267,413,-2180,-17731, -50533,110176,1966797,9938669,8638718,-278475061, -2540956509,-9816860358,27172288399,725503033401, 5592543175252,15823587507881,-168392610536153, -2848115497132448,-20819319685262839] |