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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | -22 |
| 2 | 209 |
| 3 | -1122 |
| 4 | 3894 |
| 5 | -10956 |
| 6 | 35123 |
| 7 | -120362 |
| 8 | 337106 |
| 9 | -821854 |
| 10 | 2257728 |
| 11 | -6472050 |
| 12 | 15946777 |
| 13 | -37180990 |
| 14 | 95117858 |
| 15 | -239904786 |
| 16 | 552195127 |
| 17 | -1268645554 |
| 18 | 3023055717 |
| 19 | -7022547026 |
| 20 | 15717464257 |
| 21 | -35081020348 |
[1,-22,209,-1122,3894,-10956,35123,-120362,337106, -821854,2257728,-6472050,15946777,-37180990, 95117858,-239904786,552195127,-1268645554, 3023055717,-7022547026,15717464257,-35081020348] |