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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | -2 |
| 3 | 11 |
| 4 | -28 |
| 5 | 81 |
| 6 | -234 |
| 7 | 739 |
| 8 | -2216 |
| 9 | 6545 |
| 10 | -19594 |
| 11 | 59139 |
| 12 | -177408 |
| 13 | 531181 |
| 14 | -1593614 |
| 15 | 4783799 |
| 16 | -14351032 |
| 17 | 43044597 |
| 18 | -129133854 |
| 19 | 387426799 |
| 20 | -1162281332 |
| 21 | 3486765521 |
| 22 | -10460293354 |
| 23 | 31381119459 |
| 24 | -94143358440 |
| 25 | 282429356977 |
| 26 | -847288080362 |
| 27 | 2541866366171 |
[1,-2,11,-28,81,-234,739,-2216,6545,-19594,59139, -177408,531181,-1593614,4783799,-14351032, 43044597,-129133854,387426799,-1162281332, 3486765521,-10460293354,31381119459,-94143358440, 282429356977,-847288080362,2541866366171] |