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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 10 |
| 3 | 64 |
| 4 | 489 |
| 5 | 3599 |
| 6 | 27803 |
| 7 | 212771 |
| 8 | 1656545 |
| 9 | 12904694 |
| 10 | 101255205 |
| 11 | 796288843 |
| 12 | 6286246396 |
| 13 | 49736262634 |
| 14 | 394474774687 |
| 15 | 3134464364251 |
| 16 | 24950223830205 |
| 17 | 198897142545467 |
| 18 | 1587722400605459 |
| 19 | 12689418744067169 |
| 20 | 101527684281703007 |
[2,10,64,489,3599,27803,212771,1656545,12904694, 101255205,796288843,6286246396,49736262634, 394474774687,3134464364251,24950223830205, 198897142545467,1587722400605459, 12689418744067169,101527684281703007] |