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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | -2 |
| 2 | -6 |
| 3 | -40 |
| 4 | -386 |
| 5 | -4952 |
| 6 | -77116 |
| 7 | -1406164 |
| 8 | -29389570 |
| 9 | -692122610 |
| 10 | -18136684128 |
| 11 | -523599632000 |
| 12 | -16516245738140 |
| 13 | -565284631133600 |
| 14 | -20867650682241704 |
| 15 | -826570263691236456 |
| 16 | -34971594470460748146 |
| 17 | -1574134630989710480092 |
[1,-2,-6,-40,-386,-4952,-77116,-1406164,-29389570, -692122610,-18136684128,-523599632000, -16516245738140,-565284631133600, -20867650682241704,-826570263691236456, -34971594470460748146,-1574134630989710480092] |