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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | -2 |
| 2 | -10 |
| 3 | 0 |
| 4 | -130 |
| 5 | 256 |
| 6 | 236 |
| 7 | 0 |
| 8 | -22730 |
| 9 | 81920 |
| 10 | 327668 |
| 11 | 0 |
| 12 | 777260 |
| 13 | 0 |
| 14 | -7180840 |
| 15 | 0 |
| 16 | -1051237338 |
| 17 | 4362076160 |
| 18 | 22662123300 |
| 19 | 0 |
| 20 | 227431418372 |
| 21 | -549755813888 |
| 22 | -1598030872600 |
| 23 | 0 |
| 24 | -7086115747780 |
| 25 | -32435593019392 |
| 26 | -311555637408376 |
| 27 | 0 |
[1,-2,-10,0,-130,256,236,0,-22730,81920,327668,0, 777260,0,-7180840,0,-1051237338,4362076160, 22662123300,0,227431418372,-549755813888, -1598030872600,0,-7086115747780,-32435593019392, -311555637408376,0] |