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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | -1 |
| 2 | 3 |
| 3 | -15 |
| 4 | 93 |
| 5 | -725 |
| 6 | 6815 |
| 7 | -74627 |
| 8 | 933849 |
| 9 | -13148361 |
| 10 | 205690779 |
| 11 | -3539545559 |
| 12 | 66446203637 |
| 13 | -1351309774685 |
| 14 | 29595401433975 |
| 15 | -694475294514315 |
| 16 | 17382734374217265 |
| 17 | -462283425487469585 |
| 18 | 13017336622169166515 |
| 19 | -386916316537712637215 |
| 20 | 12105656546432789499405 |
| 21 | -397693919494074869853285 |
[1,-1,3,-15,93,-725,6815,-74627,933849,-13148361, 205690779,-3539545559,66446203637,-1351309774685, 29595401433975,-694475294514315,17382734374217265, -462283425487469585,13017336622169166515, -386916316537712637215,12105656546432789499405, -397693919494074869853285] |