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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | -2 |
| 3 | -6 |
| 4 | -14 |
| 5 | -26 |
| 6 | -30 |
| 7 | 30 |
| 8 | 330 |
| 9 | 1286 |
| 10 | 3538 |
| 11 | 6910 |
| 12 | 5434 |
| 13 | -28618 |
| 14 | -182302 |
| 15 | -654098 |
| 16 | -1693750 |
| 17 | -2852570 |
| 18 | 264050 |
| 19 | 25822302 |
| 20 | 126877786 |
| 21 | 411465750 |
| 22 | 956711938 |
| 23 | 1191638734 |
| 24 | -2480333334 |
| 25 | -23263594746 |
| 26 | -96124321390 |
[1,0,-2,-6,-14,-26,-30,30,330,1286,3538,6910,5434, -28618,-182302,-654098,-1693750,-2852570,264050, 25822302,126877786,411465750,956711938,1191638734, -2480333334,-23263594746,-96124321390] |