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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | -1 |
| 3 | 2 |
| 4 | -7 |
| 5 | 24 |
| 6 | -90 |
| 7 | 345 |
| 8 | -1373 |
| 9 | 5610 |
| 10 | -23418 |
| 11 | 99373 |
| 12 | -427370 |
| 13 | 1858665 |
| 14 | -8160629 |
| 15 | 36123158 |
| 16 | -161033302 |
| 17 | 722322008 |
| 18 | -3257737848 |
| 19 | 14764170412 |
| 20 | -67202964003 |
| 21 | 307090370840 |
| 22 | -1408254347355 |
| 23 | 6478788726514 |
| 24 | -29893940649690 |
| 25 | 138306656545279 |
| 26 | -641475676394960 |
| 27 | 2982029118960410 |
[1,-1,2,-7,24,-90,345,-1373,5610,-23418,99373, -427370,1858665,-8160629,36123158,-161033302, 722322008,-3257737848,14764170412,-67202964003, 307090370840,-1408254347355,6478788726514, -29893940649690,138306656545279,-641475676394960, 2982029118960410] |