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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | -7 |
| 3 | -32 |
| 4 | 240 |
| 5 | 2528 |
| 6 | -34112 |
| 7 | -563712 |
| 8 | 10987520 |
| 9 | 247459840 |
| 10 | -7297638400 |
| 11 | -222713856000 |
| 12 | 8349585408000 |
| 13 | 338297978880000 |
| 14 | -14712528568320000 |
| 15 | -684369944248320000 |
| 16 | 36606670004551680000 |
| 17 | 2142049437446307840000 |
| 18 | -131713035645097082880000 |
[2,-7,-32,240,2528,-34112,-563712,10987520, 247459840,-7297638400,-222713856000,8349585408000, 338297978880000,-14712528568320000, -684369944248320000,36606670004551680000, 2142049437446307840000,-131713035645097082880000] |