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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | -4 |
| 3 | 4 |
| 4 | 156 |
| 5 | -1212 |
| 6 | 5628 |
| 7 | 196 |
| 8 | -251620 |
| 9 | 2500484 |
| 10 | -12608772 |
| 11 | 16004 |
| 12 | 671151260 |
| 13 | -7039845180 |
| 14 | 37258827516 |
| 15 | 1585476 |
| 16 | -2133978944740 |
| 17 | 23052545651460 |
| 18 | -125166709730820 |
| 19 | 174117124 |
| 20 | 7480512144282780 |
| 21 | -82265332158299580 |
| 22 | 453899597102224380 |
| 23 | 20390254020 |
[1,4,-4,4,156,-1212,5628,196,-251620,2500484, -12608772,16004,671151260,-7039845180,37258827516, 1585476,-2133978944740,23052545651460, -125166709730820,174117124,7480512144282780, -82265332158299580,453899597102224380,20390254020] |