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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 1 |
| 3 | 0 |
| 4 | 5 |
| 5 | -20 |
| 6 | 37 |
| 7 | -700 |
| 8 | 1017 |
| 9 | -28584 |
| 10 | 83769 |
| 11 | -1514040 |
| 12 | 9304605 |
| 13 | -108745468 |
| 14 | 1172343421 |
| 15 | -11027747380 |
| 16 | 169643707825 |
| 17 | -1567659515472 |
| 18 | 28786470143025 |
| 19 | -295814371937904 |
| 20 | 5793951884450549 |
| 21 | -69644639946402276 |
[1,0,1,0,5,-20,37,-700,1017,-28584,83769,-1514040, 9304605,-108745468,1172343421,-11027747380, 169643707825,-1567659515472,28786470143025, -295814371937904,5793951884450549, -69644639946402276] |