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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | -4 |
| 3 | 84 |
| 4 | -4320 |
| 5 | 418320 |
| 6 | -66225600 |
| 7 | 15657364800 |
| 8 | -5187108326400 |
| 9 | 2296766568096000 |
| 10 | -1310785979158656000 |
| 11 | 937056917610253440000 |
| 12 | -820081468493365478400000 |
| 13 | 862301491174096979765760000 |
[1,-4,84,-4320,418320,-66225600,15657364800, -5187108326400,2296766568096000, -1310785979158656000,937056917610253440000, -820081468493365478400000, 862301491174096979765760000] |