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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | -24 |
| 2 | 312 |
| 3 | -2912 |
| 4 | 21816 |
| 5 | -139152 |
| 6 | 783328 |
| 7 | -3986112 |
| 8 | 18650424 |
| 9 | -81251896 |
| 10 | 332798544 |
| 11 | -1291339296 |
| 12 | 4776117216 |
| 13 | -16922753616 |
| 14 | 57683178432 |
| 15 | -189821722688 |
| 16 | 604884735288 |
| 17 | -1871370360240 |
| 18 | 5633654421720 |
[1,-24,312,-2912,21816,-139152,783328,-3986112, 18650424,-81251896,332798544,-1291339296, 4776117216,-16922753616,57683178432,-189821722688, 604884735288,-1871370360240,5633654421720] |