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| n | a(n) |
|---|---|
| 1 | 3 |
| 2 | 12 |
| 3 | 1080 |
| 4 | 18506880 |
| 5 | 2198278051200 |
| 6 | 28657168334177779210174055055360000 |
[3,12,1080,18506880,2198278051200, 28657168334177779210174055055360000] |