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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 120 |
| 5 | 180 |
| 6 | 36288 |
| 7 | 6720 |
| 8 | 24710400 |
| 9 | 227026800 |
| 10 | 12108096000 |
| 11 | 121080960 |
| 12 | 197110116403200 |
| 13 | 67365043200 |
| 14 | 201490341212160000 |
| 15 | 1001829765736800000 |
| 16 | 850009620666286080000 |
| 17 | 2144384782848000 |
| 18 | 5991810785878910952960000 |
[1,2,6,120,180,36288,6720,24710400,227026800, 12108096000,121080960,197110116403200,67365043200, 201490341212160000,1001829765736800000, 850009620666286080000,2144384782848000, 5991810785878910952960000] |