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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | -1 |
| 2 | -1 |
| 3 | -1 |
| 4 | 1 |
| 5 | 11 |
| 6 | 37 |
| 7 | 209 |
| 8 | 113 |
| 9 | 23 |
| 10 | -4381 |
| 11 | -84389 |
| 12 | -310517 |
| 13 | -4103887 |
| 14 | -25059901 |
| 15 | -274436401 |
| 16 | -13182829 |
| 17 | -104362273 |
| 18 | 1748375381 |
| 19 | 690031209911 |
| 20 | 4647089032189 |
| 21 | 112233351264271 |
| 22 | 1276100569319881 |
| 23 | 2131681036523177 |
| 24 | 71497025649480187 |
| 25 | 1365106755339875117 |
[1,-1,-1,-1,1,11,37,209,113,23,-4381,-84389, -310517,-4103887,-25059901,-274436401,-13182829, -104362273,1748375381,690031209911,4647089032189, 112233351264271,1276100569319881,2131681036523177, 71497025649480187,1365106755339875117] |