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| n | a(n) |
|---|---|
| 1 | -3 |
| 2 | 2 |
| 3 | 2 |
| 4 | -8 |
| 5 | 16 |
| 6 | -16 |
| 7 | 80 |
| 8 | 384 |
| 9 | 4160 |
| 10 | 43008 |
| 11 | 494336 |
| 12 | 6136832 |
| 13 | 82118656 |
| 14 | 1178294272 |
| 15 | 18053433344 |
| 16 | 294241402880 |
| 17 | 5083946115072 |
| 18 | 92835116318720 |
| 19 | 1786595439869952 |
| 20 | 36144509314138112 |
| 21 | 766933328068345856 |
[-3,2,2,-8,16,-16,80,384,4160,43008,494336, 6136832,82118656,1178294272,18053433344, 294241402880,5083946115072,92835116318720, 1786595439869952,36144509314138112, 766933328068345856] |