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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | -1 |
| 2 | 9 |
| 3 | -105 |
| 4 | 1393 |
| 5 | -71025 |
| 6 | -898887 |
| 7 | -455252889 |
| 8 | -75822681503 |
| 9 | -21366754787169 |
| 10 | -7036035942040855 |
| 11 | -2891117170991668553 |
| 12 | -1426147181806835610927 |
| 13 | -835104626729810211267025 |
[1,-1,9,-105,1393,-71025,-898887,-455252889, -75822681503,-21366754787169,-7036035942040855, -2891117170991668553,-1426147181806835610927, -835104626729810211267025] |