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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 1 |
| 3 | -3 |
| 4 | 11 |
| 5 | -50 |
| 6 | 394 |
| 7 | -4284 |
| 8 | 51708 |
| 9 | -653904 |
| 10 | 8861256 |
| 11 | -132180840 |
| 12 | 2186984040 |
| 13 | -39706739280 |
| 14 | 779193951600 |
| 15 | -16356660384960 |
| 16 | 365503727198400 |
| 17 | -8673545006246400 |
| 18 | 218077259881872000 |
| 19 | -5792698031011056000 |
[0,0,1,-3,11,-50,394,-4284,51708,-653904,8861256, -132180840,2186984040,-39706739280,779193951600, -16356660384960,365503727198400,-8673545006246400, 218077259881872000,-5792698031011056000] |