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| n | a(n) |
|---|---|
| 1 | 9 |
| 2 | 81 |
| 3 | 333 |
| 4 | 1360 |
| 5 | 6092 |
| 6 | 25689 |
| 7 | 105690 |
| 8 | 439332 |
| 9 | 1821924 |
| 10 | 7521414 |
| 11 | 31063445 |
| 12 | 128325745 |
| 13 | 529821580 |
| 14 | 2187257369 |
| 15 | 9030334421 |
| 16 | 37280871533 |
| 17 | 153905038835 |
| 18 | 635365800266 |
| 19 | 2622977336044 |
| 20 | 10828351058245 |
| 21 | 44702329730212 |
[9,81,333,1360,6092,25689,105690,439332,1821924, 7521414,31063445,128325745,529821580,2187257369, 9030334421,37280871533,153905038835,635365800266, 2622977336044,10828351058245,44702329730212] |