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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | -1 |
| 2 | 0 |
| 3 | 2 |
| 4 | -2 |
| 5 | 18 |
| 6 | -128 |
| 7 | 740 |
| 8 | -3204 |
| 9 | -6076 |
| 10 | 210304 |
| 11 | -1097064 |
| 12 | -29284760 |
| 13 | 398231768 |
| 14 | 792490752 |
| 15 | -124480674448 |
| 16 | 1471405254928 |
| 17 | -2684728872720 |
| 18 | -64686947480576 |
| 19 | -626709774748384 |
| 20 | -10524779012515104 |
| 21 | 689522178752789024 |
| 22 | 34910956277827256320 |
[1,-1,0,2,-2,18,-128,740,-3204,-6076,210304, -1097064,-29284760,398231768,792490752, -124480674448,1471405254928,-2684728872720, -64686947480576,-626709774748384, -10524779012515104,689522178752789024, 34910956277827256320] |