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| n | a(n) |
|---|---|
| 0 | -1 |
| 1 | 3 |
| 2 | -16 |
| 3 | 126 |
| 4 | -1320 |
| 5 | 17280 |
| 6 | -271440 |
| 7 | 4974480 |
| 8 | -104186880 |
| 9 | 2454883200 |
| 10 | -64269676800 |
| 11 | 1850862182400 |
| 12 | -58147441228800 |
| 13 | 1979015707468800 |
| 14 | -72535825410048000 |
| 15 | 2848518844883712000 |
| 16 | -119320306456006656000 |
| 17 | 5310538503447969792000 |
[-1,3,-16,126,-1320,17280,-271440,4974480, -104186880,2454883200,-64269676800,1850862182400, -58147441228800,1979015707468800, -72535825410048000,2848518844883712000, -119320306456006656000,5310538503447969792000] |