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| n | a(n) |
|---|---|
| 1 | 21 |
| 2 | 480 |
| 3 | 6241 |
| 4 | 125765 |
| 5 | 2607478 |
| 6 | 52756072 |
| 7 | 1109882746 |
| 8 | 23359296497 |
| 9 | 492457987101 |
| 10 | 10402250973413 |
| 11 | 219775565244891 |
| 12 | 4644590743236824 |
| 13 | 98165206674288770 |
| 14 | 2074840058451866478 |
| 15 | 43855171635171730011 |
| 16 | 926958389641748039690 |
[21,480,6241,125765,2607478,52756072,1109882746, 23359296497,492457987101,10402250973413, 219775565244891,4644590743236824, 98165206674288770,2074840058451866478, 43855171635171730011,926958389641748039690] |