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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | -3 |
| 3 | -12 |
| 4 | -100 |
| 5 | -1749 |
| 6 | -47600 |
| 7 | -800681 |
| 8 | -39453535 |
| 9 | -1351201968 |
| 10 | -66984136299 |
| 11 | -2938096403400 |
| 12 | -235011452211680 |
[1,1,-3,-12,-100,-1749,-47600,-800681,-39453535, -1351201968,-66984136299,-2938096403400, -235011452211680] |