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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 7 |
| 4 | 32 |
| 5 | 141 |
| 6 | -48 |
| 7 | -20509 |
| 8 | -572416 |
| 9 | -13236455 |
| 10 | -290711040 |
| 11 | -6196120193 |
| 12 | -125279895552 |
| 13 | -2200506714587 |
| 14 | -21844509804544 |
| 15 | 731664799971163 |
| 16 | 69257460487553024 |
| 17 | 3772508483052129329 |
| 18 | 174474102931077464064 |
| 19 | 7365599642083503837175 |
| 20 | 286164434343334028247040 |
[1,2,7,32,141,-48,-20509,-572416,-13236455, -290711040,-6196120193,-125279895552, -2200506714587,-21844509804544,731664799971163, 69257460487553024,3772508483052129329, 174474102931077464064,7365599642083503837175, 286164434343334028247040] |