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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | -1 |
| 3 | 5 |
| 4 | -12 |
| 5 | 29 |
| 6 | -165 |
| 7 | 993 |
| 8 | -7056 |
| 9 | 58617 |
| 10 | -520065 |
| 11 | 5139485 |
| 12 | -56499564 |
| 13 | 676947413 |
| 14 | -8785333557 |
| 15 | 122824831353 |
| 16 | -1839706861440 |
| 17 | 29397288124913 |
| 18 | -499197383688033 |
| 19 | 8976479629200565 |
| 20 | -170396114982640300 |
| 21 | 3405066284386654349 |
[0,1,-1,5,-12,29,-165,993,-7056,58617,-520065, 5139485,-56499564,676947413,-8785333557, 122824831353,-1839706861440,29397288124913, -499197383688033,8976479629200565, -170396114982640300,3405066284386654349] |