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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | -4 |
| 3 | 8 |
| 4 | 912 |
| 5 | -99168 |
| 6 | 11815872 |
| 7 | -1790856576 |
| 8 | 347783278848 |
| 9 | -85244795874816 |
| 10 | 25888104843574272 |
| 11 | -9570587679263078400 |
| 12 | 4239434238319441121280 |
| 13 | -2218976274384029204766720 |
[1,2,-4,8,912,-99168,11815872,-1790856576, 347783278848,-85244795874816,25888104843574272, -9570587679263078400,4239434238319441121280, -2218976274384029204766720] |