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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | -1 |
| 2 | -1 |
| 3 | 2 |
| 4 | 5 |
| 5 | -16 |
| 6 | -61 |
| 7 | 272 |
| 8 | 1385 |
| 9 | -7936 |
| 10 | -50521 |
| 11 | 353792 |
| 12 | 2702765 |
| 13 | -22368256 |
| 14 | -199360981 |
| 15 | 1903757312 |
| 16 | 19391512145 |
| 17 | -209865342976 |
| 18 | -2404879675441 |
| 19 | 29088885112832 |
| 20 | 370371188237525 |
| 21 | -4951498053124096 |
| 22 | -69348874393137901 |
[0,-1,-1,2,5,-16,-61,272,1385,-7936,-50521,353792, 2702765,-22368256,-199360981,1903757312, 19391512145,-209865342976,-2404879675441, 29088885112832,370371188237525,-4951498053124096, -69348874393137901] |