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| n | a(n) |
|---|---|
| 3 | 21 |
| 4 | 231 |
| 5 | 3003 |
| 6 | 43758 |
| 7 | 692835 |
| 8 | 11685817 |
| 9 | 207157665 |
| 10 | 3823000545 |
| 11 | 72931087320 |
| 12 | 1430571328200 |
| 13 | 28734046963560 |
| 14 | 589047962752980 |
| 15 | 12292044987448215 |
| 16 | 260543149635912165 |
| 17 | 5599392250947235125 |
| 18 | 121830987186399315825 |
[21,231,3003,43758,692835,11685817,207157665, 3823000545,72931087320,1430571328200, 28734046963560,589047962752980,12292044987448215, 260543149635912165,5599392250947235125, 121830987186399315825] |