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| n | a(n) |
|---|---|
| 5 | 120 |
| 6 | 4320 |
| 7 | 105840 |
| 8 | 2257920 |
| 9 | 45722880 |
| 10 | 914457600 |
| 11 | 18441561600 |
| 12 | 379369267200 |
| 13 | 8014175769600 |
| 14 | 174530938982400 |
| 15 | 3926946127104000 |
| 16 | 91390746230784000 |
| 17 | 2200993805058048000 |
| 18 | 54855537910677504000 |
| 19 | 1414489227553898496000 |
| 20 | 37719712734770626560000 |
[120,4320,105840,2257920,45722880,914457600, 18441561600,379369267200,8014175769600, 174530938982400,3926946127104000, 91390746230784000,2200993805058048000, 54855537910677504000,1414489227553898496000, 37719712734770626560000] |