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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | -254 |
| 3 | -6555 |
| 4 | -65512 |
| 5 | -390505 |
| 6 | -1678896 |
| 7 | -5759761 |
| 8 | -16736896 |
| 9 | -42683841 |
| 10 | -96371200 |
| 11 | -174442081 |
| 12 | 49019904 |
| 13 | 5411290079 |
| 14 | 85702502144 |
| 15 | 1305111477375 |
| 16 | 20918494920704 |
| 17 | 355680452338559 |
| 18 | 6402362685767424 |
| 19 | 121645083425268959 |
| 20 | 2432901982576640000 |
[1,0,-254,-6555,-65512,-390505,-1678896,-5759761, -16736896,-42683841,-96371200,-174442081,49019904, 5411290079,85702502144,1305111477375, 20918494920704,355680452338559,6402362685767424, 121645083425268959,2432901982576640000] |