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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | -3 |
| 3 | 8 |
| 4 | -18 |
| 5 | 44 |
| 6 | -80 |
| 7 | 272 |
| 8 | 112 |
| 9 | 5280 |
| 10 | 38464 |
| 11 | 414336 |
| 12 | 4573184 |
| 13 | 55680000 |
| 14 | 731374592 |
| 15 | 10335551488 |
| 16 | 156303374336 |
| 17 | 2518984953856 |
| 18 | 43099088904192 |
| 19 | 780268881068032 |
| 20 | 14902336355991552 |
| 21 | 299452809651617792 |
| 22 | 6315501510330286080 |
| 23 | 139485953831281098752 |
| 24 | 3219718099932087844864 |
[0,1,-3,8,-18,44,-80,272,112,5280,38464,414336, 4573184,55680000,731374592,10335551488, 156303374336,2518984953856,43099088904192, 780268881068032,14902336355991552, 299452809651617792,6315501510330286080, 139485953831281098752,3219718099932087844864] |