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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 12 |
| 4 | 2448 |
| 5 | 6828480 |
| 6 | 1386834134400 |
| 7 | 20251525440458995200 |
| 8 | 33182473074940946503237478400 |
[1,2,12,2448,6828480,1386834134400, 20251525440458995200, 33182473074940946503237478400] |