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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | -1 |
| 2 | -3 |
| 3 | -1 |
| 4 | 69 |
| 5 | 455 |
| 6 | -1155 |
| 7 | -50065 |
| 8 | -334155 |
| 9 | 4107095 |
| 10 | 112058925 |
| 11 | 491352575 |
| 12 | -24429589275 |
| 13 | -535893782425 |
| 14 | 606194735325 |
| 15 | 249291355871375 |
| 16 | 4380933801391125 |
| 17 | -56204145098271625 |
| 18 | -4031655689182933875 |
[1,-1,-3,-1,69,455,-1155,-50065,-334155,4107095, 112058925,491352575,-24429589275,-535893782425, 606194735325,249291355871375,4380933801391125, -56204145098271625,-4031655689182933875] |