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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | -1 |
| 2 | -4 |
| 3 | -23 |
| 4 | -225 |
| 5 | -2765 |
| 6 | -42291 |
| 7 | -758931 |
| 8 | -15672042 |
| 9 | -365632740 |
| 10 | -9512462314 |
| 11 | -273071185192 |
| 12 | -8574979449941 |
| 13 | -292421476560437 |
| 14 | -10762598186760785 |
| 15 | -425244979326332068 |
| 16 | -17953805056325313497 |
| 17 | -806668085786772161511 |
[1,-1,-4,-23,-225,-2765,-42291,-758931,-15672042, -365632740,-9512462314,-273071185192, -8574979449941,-292421476560437, -10762598186760785,-425244979326332068, -17953805056325313497,-806668085786772161511] |