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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | -7 |
| 3 | 21 |
| 4 | 49 |
| 5 | -595 |
| 6 | -1911 |
| 7 | 39109 |
| 8 | 165473 |
| 9 | -4525731 |
| 10 | -23883335 |
| 11 | 805349237 |
| 12 | 5097585297 |
| 13 | -203564524787 |
| 14 | -1503073984279 |
| 15 | 69292329479205 |
| 16 | 584713994953921 |
| 17 | -30553447357629763 |
| 18 | -290046835163027943 |
| 19 | 16939595863125337813 |
| 20 | 178676615255242261745 |
[0,1,-7,21,49,-595,-1911,39109,165473,-4525731, -23883335,805349237,5097585297,-203564524787, -1503073984279,69292329479205,584713994953921, -30553447357629763,-290046835163027943, 16939595863125337813,178676615255242261745] |