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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | -3 |
| 3 | 9 |
| 4 | -27 |
| 5 | 78 |
| 6 | -219 |
| 7 | 591 |
| 8 | -1500 |
| 9 | 3420 |
| 10 | -6153 |
| 11 | 3315 |
| 12 | 44466 |
| 13 | -324276 |
| 14 | 1627002 |
| 15 | -7069893 |
| 16 | 28345875 |
| 17 | -107618916 |
| 18 | 391749108 |
| 19 | -1375531170 |
| 20 | 4669215090 |
| 21 | -15311251593 |
| 22 | 48316101369 |
| 23 | -145501913850 |
| 24 | 411323278248 |
| 25 | -1053727809204 |
| 26 | 2226156968586 |
| 27 | -2433380638410 |
| 28 | -10543933246791 |
[1,-3,9,-27,78,-219,591,-1500,3420,-6153,3315, 44466,-324276,1627002,-7069893,28345875, -107618916,391749108,-1375531170,4669215090, -15311251593,48316101369,-145501913850, 411323278248,-1053727809204,2226156968586, -2433380638410,-10543933246791] |