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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | -15 |
| 2 | 90 |
| 3 | -275 |
| 4 | 555 |
| 5 | -1653 |
| 6 | 6185 |
| 7 | -14745 |
| 8 | 27390 |
| 9 | -77370 |
| 10 | 222210 |
| 11 | -454050 |
| 12 | 935885 |
| 13 | -2388795 |
| 14 | 5531835 |
| 15 | -11402626 |
| 16 | 24305100 |
| 17 | -53821020 |
| 18 | 117704765 |
| 19 | -244275885 |
| 20 | 494231898 |
| 21 | -1048892855 |
| 22 | 2216119785 |
| 23 | -4418663160 |
| 24 | 8855734025 |
[1,-15,90,-275,555,-1653,6185,-14745,27390,-77370, 222210,-454050,935885,-2388795,5531835,-11402626, 24305100,-53821020,117704765,-244275885,494231898, -1048892855,2216119785,-4418663160,8855734025] |