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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | -3 |
| 4 | 13 |
| 5 | -65 |
| 6 | 351 |
| 7 | -1989 |
| 8 | 11650 |
| 9 | -69900 |
| 10 | 427168 |
| 11 | -2648444 |
| 12 | 16612986 |
| 13 | -105215708 |
| 14 | 671762688 |
| 15 | -4318480068 |
| 16 | 27926208102 |
| 17 | -181520595372 |
| 18 | 1185224306328 |
| 19 | -7769814296892 |
| 20 | 51117268739082 |
| 21 | -337374433220892 |
| 22 | 2233100488061696 |
| 23 | -14819687150440940 |
| 24 | 98583271355649642 |
| 25 | -657222710894636084 |
[1,1,-3,13,-65,351,-1989,11650,-69900,427168, -2648444,16612986,-105215708,671762688, -4318480068,27926208102,-181520595372, 1185224306328,-7769814296892,51117268739082, -337374433220892,2233100488061696, -14819687150440940,98583271355649642, -657222710894636084] |