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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 3 |
| 4 | 4 |
| 5 | 5 |
| 6 | 6 |
| 7 | 10 |
| 8 | 15 |
| 9 | 45 |
| 10 | 120 |
| 11 | 990 |
| 12 | 14190 |
| 13 | 489555 |
| 14 | 161226780 |
| 15 | 476106503180 |
| 16 | 19554673086218985 |
| 17 | 698490144518203427450060 |
| 18 | 17987097565293886931115539020016860 |
| 19 | 1246236391932004987381133823926620650891666994820 |
[1,2,3,4,5,6,10,15,45,120,990,14190,489555, 161226780,476106503180,19554673086218985, 698490144518203427450060, 17987097565293886931115539020016860, 1246236391932004987381133823926620650891666994820] |