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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | -11 |
| 4 | 45 |
| 5 | -135 |
| 6 | 297 |
| 7 | -198 |
| 8 | -1872 |
| 9 | 15705 |
| 10 | -103695 |
| 11 | 556749 |
| 12 | -2275131 |
| 13 | 6904116 |
| 14 | -15392760 |
| 15 | 38895675 |
| 16 | -278647283 |
| 17 | 2238863647 |
| 18 | -12869710817 |
| 19 | 53512462775 |
| 20 | -155088202345 |
| 21 | 174598433696 |
| 22 | 1545643834686 |
| 23 | -15193843495341 |
| 24 | 84540206058435 |
| 25 | -303767647556085 |
| 26 | 263679736843551 |
[1,1,-11,45,-135,297,-198,-1872,15705,-103695, 556749,-2275131,6904116,-15392760,38895675, -278647283,2238863647,-12869710817,53512462775, -155088202345,174598433696,1545643834686, -15193843495341,84540206058435,-303767647556085, 263679736843551] |