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| n | a(n) |
|---|---|
| 4 | 1 |
| 5 | 48 |
| 6 | 4320 |
| 7 | 638400 |
| 8 | 143216640 |
| 9 | 45912303360 |
| 10 | 20064844800000 |
| 11 | 11517786190310400 |
| 12 | 8429182295998464000 |
| 13 | 7676025035655591014400 |
| 14 | 8524944488872455752908800 |
| 15 | 11353372433362159200000000000 |
| 16 | 17873609218353722680651284480000 |
| 17 | 32855463684946243953215776972800000 |
| 18 | 69770867798960701944675685147607040000 |
[1,48,4320,638400,143216640,45912303360, 20064844800000,11517786190310400, 8429182295998464000,7676025035655591014400, 8524944488872455752908800, 11353372433362159200000000000, 17873609218353722680651284480000, 32855463684946243953215776972800000, 69770867798960701944675685147607040000] |