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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | -1 |
| 3 | 3 |
| 4 | 0 |
| 5 | -65 |
| 6 | 525 |
| 7 | -3619 |
| 8 | 15512 |
| 9 | 51549 |
| 10 | -2308365 |
| 11 | 37073399 |
| 12 | -417301896 |
| 13 | 2878576779 |
| 14 | 13832070161 |
| 15 | -1001340728543 |
| 16 | 23330589314640 |
| 17 | -373263648419975 |
| 18 | 3611687964249159 |
| 19 | 21971926549737643 |
| 20 | -2211581913138852400 |
[0,1,-1,3,0,-65,525,-3619,15512,51549,-2308365, 37073399,-417301896,2878576779,13832070161, -1001340728543,23330589314640,-373263648419975, 3611687964249159,21971926549737643, -2211581913138852400] |