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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | -3 |
| 3 | 21 |
| 4 | -235 |
| 5 | 3630 |
| 6 | -71631 |
| 7 | 1721671 |
| 8 | -48804183 |
| 9 | 1594177605 |
| 10 | -58963348675 |
| 11 | 2435865852156 |
| 12 | -111169287046467 |
| 13 | 5554808694622369 |
| 14 | -301609325982387255 |
| 15 | 17682700497003095625 |
| 16 | -1113293610926803531951 |
| 17 | 74915504280675843548274 |
| 18 | -5365793673423031533999147 |
[1,-3,21,-235,3630,-71631,1721671,-48804183, 1594177605,-58963348675,2435865852156, -111169287046467,5554808694622369, -301609325982387255,17682700497003095625, -1113293610926803531951,74915504280675843548274, -5365793673423031533999147] |