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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | -1 |
| 3 | 1 |
| 4 | -17 |
| 5 | 31 |
| 6 | -691 |
| 7 | 5461 |
| 8 | -929569 |
| 9 | 3202291 |
| 10 | -221930581 |
| 11 | 4722116521 |
| 12 | -968383680827 |
| 13 | 14717667114151 |
| 14 | -2093660879252671 |
| 15 | 86125672563201181 |
| 16 | -129848163681107301953 |
| 17 | 868320396104950823611 |
| 18 | -209390615747646519456961 |
| 19 | 14129659550745551130667441 |
| 20 | -8486725345098385062639014237 |
[1,-1,1,-17,31,-691,5461,-929569,3202291, -221930581,4722116521,-968383680827, 14717667114151,-2093660879252671, 86125672563201181,-129848163681107301953, 868320396104950823611,-209390615747646519456961, 14129659550745551130667441, -8486725345098385062639014237] |