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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | -1 |
| 2 | -1 |
| 3 | -17 |
| 4 | -31 |
| 5 | -691 |
| 6 | -5461 |
| 7 | -929569 |
| 8 | -3202291 |
| 9 | -221930581 |
| 10 | -4722116521 |
| 11 | -56963745931 |
| 12 | -14717667114151 |
| 13 | -2093660879252671 |
| 14 | -86125672563201181 |
| 15 | -129848163681107301953 |
| 16 | -868320396104950823611 |
| 17 | -209390615747646519456961 |
| 18 | -14129659550745551130667441 |
[1,-1,-1,-17,-31,-691,-5461,-929569,-3202291, -221930581,-4722116521,-56963745931, -14717667114151,-2093660879252671, -86125672563201181,-129848163681107301953, -868320396104950823611,-209390615747646519456961, -14129659550745551130667441] |