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| n | a(n) |
|---|---|
| 1 | 21347 |
| 2 | 2213347 |
| 3 | 2213447 |
| 4 | 21334447 |
| 5 | 21344447 |
| 6 | 21344777 |
| 7 | 22133477 |
| 8 | 213334477 |
| 9 | 221344477 |
| 10 | 2134444777 |
| 11 | 22133344447 |
| 12 | 221344477777 |
| 13 | 2133344447777 |
| 14 | 2133347777777 |
| 15 | 2213447777777 |
| 16 | 22133344447777 |
| 17 | 213344447777777 |
| 18 | 221333447777777 |
| 19 | 22133344447777777 |
[21347,2213347,2213447,21334447,21344447,21344777, 22133477,213334477,221344477,2134444777, 22133344447,221344477777,2133344447777, 2133347777777,2213447777777,22133344447777, 213344447777777,221333447777777,22133344447777777] |