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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 6 |
| 2 | 18 |
| 3 | -288 |
| 4 | -1890 |
| 5 | 41472 |
| 6 | 324324 |
| 7 | -7962624 |
| 8 | -67343562 |
| 9 | 1751777280 |
| 10 | 15489019260 |
| 11 | -417368899584 |
| 12 | -3797625904020 |
| 13 | 104791699095552 |
| 14 | 972776481568200 |
| 15 | -27305722735755264 |
| 16 | -257250740550710490 |
| 17 | 7314721255213498368 |
| 18 | 69699818292739559820 |
[1,6,18,-288,-1890,41472,324324,-7962624, -67343562,1751777280,15489019260,-417368899584, -3797625904020,104791699095552,972776481568200, -27305722735755264,-257250740550710490, 7314721255213498368,69699818292739559820] |