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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | -1 |
| 2 | 2 |
| 3 | -2 |
| 4 | 4 |
| 5 | -6 |
| 6 | 13 |
| 7 | -20 |
| 8 | 38 |
| 9 | -65 |
| 10 | 129 |
| 11 | -228 |
| 12 | 435 |
| 13 | -794 |
| 14 | 1528 |
| 15 | -2833 |
| 16 | 5421 |
| 17 | -10189 |
| 18 | 19561 |
| 19 | -37091 |
| 20 | 71247 |
| 21 | -135973 |
| 22 | 261879 |
| 23 | -502303 |
| 24 | 969181 |
| 25 | -1866210 |
| 26 | 3608664 |
| 27 | -6970576 |
| 28 | 13504298 |
| 29 | -26152744 |
| 30 | 50758711 |
| 31 | -98515611 |
| 32 | 191517618 |
| 33 | -372404560 |
| 34 | 725061378 |
[1,-1,2,-2,4,-6,13,-20,38,-65,129,-228,435,-794, 1528,-2833,5421,-10189,19561,-37091,71247,-135973, 261879,-502303,969181,-1866210,3608664,-6970576, 13504298,-26152744,50758711,-98515611,191517618, -372404560,725061378] |