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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | -1 |
| 2 | -3 |
| 3 | 1 |
| 4 | 6 |
| 5 | -1 |
| 6 | -10 |
| 7 | 1 |
| 8 | 15 |
| 9 | -1 |
| 10 | -21 |
| 11 | 1 |
| 12 | 28 |
| 13 | -1 |
| 14 | -36 |
| 15 | 1 |
| 16 | 45 |
| 17 | -1 |
| 18 | -55 |
| 19 | 1 |
| 20 | 66 |
| 21 | -1 |
| 22 | -78 |
| 23 | 1 |
| 24 | 91 |
| 25 | -1 |
| 26 | -105 |
| 27 | 1 |
| 28 | 120 |
| 29 | -1 |
| 30 | -136 |
| 31 | 1 |
| 32 | 153 |
| 33 | -1 |
| 34 | -171 |
| 35 | 1 |
| 36 | 190 |
| 37 | -1 |
| 38 | -210 |
| 39 | 1 |
| 40 | 231 |
| 41 | -1 |
| 42 | -253 |
| 43 | 1 |
| 44 | 276 |
| 45 | -1 |
| 46 | -300 |
| 47 | 1 |
| 48 | 325 |
| 49 | -1 |
| 50 | -351 |
| 51 | 1 |
| 52 | 378 |
| 53 | -1 |
| 54 | -406 |
| 55 | 1 |
| 56 | 435 |
[1,-1,-3,1,6,-1,-10,1,15,-1,-21,1,28,-1,-36,1,45, -1,-55,1,66,-1,-78,1,91,-1,-105,1,120,-1,-136,1, 153,-1,-171,1,190,-1,-210,1,231,-1,-253,1,276,-1, -300,1,325,-1,-351,1,378,-1,-406,1,435] |