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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | -1 |
| 4 | -11 |
| 5 | -25 |
| 6 | 181 |
| 7 | 2039 |
| 8 | 3109 |
| 9 | -131545 |
| 10 | -1417259 |
| 11 | 2734679 |
| 12 | 239834629 |
| 13 | 2217084935 |
| 14 | -23659572299 |
| 15 | -859070164681 |
| 16 | -5378041927451 |
| 17 | 198832696957415 |
| 18 | 5164126517703061 |
| 19 | 4868884057959959 |
| 20 | -2309488856960067131 |
[1,1,-1,-11,-25,181,2039,3109,-131545,-1417259, 2734679,239834629,2217084935,-23659572299, -859070164681,-5378041927451,198832696957415, 5164126517703061,4868884057959959, -2309488856960067131] |