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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 2 |
| 4 | -2 |
| 5 | 6 |
| 6 | -6 |
| 7 | 42 |
| 8 | -42 |
| 9 | 1806 |
| 10 | -1806 |
| 11 | 3263442 |
| 12 | -3263442 |
| 13 | 10650056950806 |
| 14 | -10650056950806 |
| 15 | 113423713055421844361000442 |
| 16 | -113423713055421844361000442 |
| 17 | 12864938683278671740537145998360961546653259485195806 |
[1,2,2,-2,6,-6,42,-42,1806,-1806,3263442,-3263442, 10650056950806,-10650056950806, 113423713055421844361000442, -113423713055421844361000442, 12864938683278671740537145998360961546653259485195\ 806] |