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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 15 |
| 3 | 87 |
| 4 | 414 |
| 5 | -333 |
| 6 | -36207 |
| 7 | -125415 |
| 8 | 9692208 |
| 9 | 65346480 |
| 10 | -6686193834 |
| 11 | -28979410023 |
| 12 | 9399236141664 |
| 13 | -74034590428035 |
| 14 | -21601690453093869 |
| 15 | 753341807730002715 |
| 16 | 64208547156310265880 |
| 17 | -6137571162315494165580 |
| 18 | -131200755856066508312736 |
[1,3,15,87,414,-333,-36207,-125415,9692208, 65346480,-6686193834,-28979410023,9399236141664, -74034590428035,-21601690453093869, 753341807730002715,64208547156310265880, -6137571162315494165580,-131200755856066508312736] |