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| n | a(n) |
|---|---|
| 1 | 7 |
| 2 | 47 |
| 3 | 307 |
| 4 | 1527 |
| 5 | 6635 |
| 6 | 27379 |
| 7 | 111311 |
| 8 | 456029 |
| 9 | 1888383 |
| 10 | 7880975 |
| 11 | 33018001 |
| 12 | 138469191 |
| 13 | 580547651 |
| 14 | 2432537637 |
| 15 | 10187801775 |
| 16 | 42657765711 |
| 17 | 178601463643 |
| 18 | 747785468741 |
| 19 | 3131002111003 |
| 20 | 13109964303805 |
| 21 | 54894127263817 |
[7,47,307,1527,6635,27379,111311,456029,1888383, 7880975,33018001,138469191,580547651,2432537637, 10187801775,42657765711,178601463643,747785468741, 3131002111003,13109964303805,54894127263817] |