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| n | a(n) |
|---|---|
| 1 | -1 |
| 2 | -2 |
| 3 | -7 |
| 4 | -40 |
| 5 | -301 |
| 6 | -2856 |
| 7 | -32299 |
| 8 | -416816 |
| 9 | -5892345 |
| 10 | -86464000 |
| 11 | -1177909711 |
| 12 | -8944121088 |
| 13 | 349846341467 |
| 14 | 29237270702080 |
| 15 | 1585383533246925 |
| 16 | 78578098584541184 |
| 17 | 3843296406581515919 |
| 18 | 190784066705549623296 |
[-1,-2,-7,-40,-301,-2856,-32299,-416816,-5892345, -86464000,-1177909711,-8944121088,349846341467, 29237270702080,1585383533246925,78578098584541184, 3843296406581515919,190784066705549623296] |