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| n | a(n) |
|---|---|
| 1 | 81 |
| 2 | 470 |
| 3 | 2180 |
| 4 | 9623 |
| 5 | 42669 |
| 6 | 192393 |
| 7 | 876277 |
| 8 | 4010555 |
| 9 | 18395493 |
| 10 | 84458827 |
| 11 | 387945181 |
| 12 | 1782308819 |
| 13 | 8189083701 |
| 14 | 37627550715 |
| 15 | 172896033837 |
| 16 | 794452690915 |
| 17 | 3650504500581 |
| 18 | 16774075855627 |
| 19 | 77076986789213 |
| 20 | 354169411790451 |
[81,470,2180,9623,42669,192393,876277,4010555, 18395493,84458827,387945181,1782308819,8189083701, 37627550715,172896033837,794452690915, 3650504500581,16774075855627,77076986789213, 354169411790451] |