| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | -1 |
| 3 | 7 |
| 4 | -26 |
| 5 | 185 |
| 6 | -1336 |
| 7 | 12367 |
| 8 | -129296 |
| 9 | 1558865 |
| 10 | -21045376 |
| 11 | 316097527 |
| 12 | -5218370816 |
| 13 | 94003171145 |
| 14 | -1834192393216 |
| 15 | 38543705698687 |
| 16 | -867785366030336 |
| 17 | 20840298552277025 |
| 18 | -531767959826169856 |
| 19 | 14366953364916735847 |
[0,1,-1,7,-26,185,-1336,12367,-129296,1558865, -21045376,316097527,-5218370816,94003171145, -1834192393216,38543705698687,-867785366030336, 20840298552277025,-531767959826169856, 14366953364916735847] |