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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | -1 |
| 4 | 2 |
| 5 | -5 |
| 6 | 12 |
| 7 | -26 |
| 8 | 52 |
| 9 | -101 |
| 10 | 201 |
| 11 | -422 |
| 12 | 927 |
| 13 | -2070 |
| 14 | 4579 |
| 15 | -9894 |
| 16 | 20789 |
| 17 | -42517 |
| 18 | 84937 |
| 19 | -166570 |
| 20 | 322700 |
| 21 | -622500 |
| 22 | 1207056 |
| 23 | -2376168 |
| 24 | 4787523 |
| 25 | -9908610 |
| 26 | 21021499 |
| 27 | -45404102 |
| 28 | 98952388 |
| 29 | -215756156 |
| 30 | 467541948 |
| 31 | -1002478352 |
| 32 | 2121546013 |
| 33 | -4427208709 |
| 34 | 9110572776 |
| 35 | -18503242145 |
| 36 | 37135048484 |
| 37 | -73759839074 |
[1,1,-1,2,-5,12,-26,52,-101,201,-422,927,-2070, 4579,-9894,20789,-42517,84937,-166570,322700, -622500,1207056,-2376168,4787523,-9908610, 21021499,-45404102,98952388,-215756156,467541948, -1002478352,2121546013,-4427208709,9110572776, -18503242145,37135048484,-73759839074] |