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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 4 |
| 3 | 14 |
| 4 | 17 |
| 5 | 31 |
| 6 | 41 |
| 7 | 131 |
| 8 | 141 |
| 9 | 241 |
| 10 | 441 |
| 11 | 1441 |
| 12 | 4441 |
| 13 | 14441 |
| 14 | 17441 |
[2,4,14,17,31,41,131,141,241,441,1441,4441,14441, 17441] |