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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 2 |
| 2 | -6 |
| 3 | 80 |
| 4 | -2310 |
| 5 | 114912 |
| 6 | -8741040 |
| 7 | 943113600 |
| 8 | -136984998150 |
| 9 | 25771171025600 |
| 10 | -6096112602836256 |
| 11 | 1770904261963549440 |
| 12 | -619781244413394663600 |
| 13 | 257206839532730597664000 |
| 14 | -124885627021632853758096000 |
| 15 | 70139282938382254349182510080 |
| 16 | -45116676897361263845107791884550 |
[0,2,-6,80,-2310,114912,-8741040,943113600, -136984998150,25771171025600,-6096112602836256, 1770904261963549440,-619781244413394663600, 257206839532730597664000, -124885627021632853758096000, 70139282938382254349182510080, -45116676897361263845107791884550] |