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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 4 |
| 4 | 7 |
| 5 | 19 |
| 6 | 31 |
| 7 | 67 |
| 8 | 391 |
| 9 | 583 |
| 10 | 4549 |
| 11 | 917467 |
| 12 | 6777061 |
| 13 | 86794921 |
| 14 | 1421517037 |
| 15 | 171234891469 |
[1,3,4,7,19,31,67,391,583,4549,917467,6777061, 86794921,1421517037,171234891469] |