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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 20 |
| 2 | 158 |
| 3 | -6520 |
| 4 | -245108 |
| 5 | 1409200 |
| 6 | 324764680 |
| 7 | 4449135200 |
| 8 | -461168663920 |
| 9 | -17836899025600 |
| 10 | 647687369505760 |
| 11 | 56119043032067200 |
| 12 | -601762916982989120 |
| 13 | -175004959304782931200 |
| 14 | -1606953049267174852480 |
| 15 | 560777741139261073856000 |
| 16 | 17048794391625066191622400 |
[1,20,158,-6520,-245108,1409200,324764680, 4449135200,-461168663920,-17836899025600, 647687369505760,56119043032067200, -601762916982989120,-175004959304782931200, -1606953049267174852480,560777741139261073856000, 17048794391625066191622400] |