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| n | a(n) |
|---|---|
| 1 | 13 |
| 2 | 31 |
| 3 | 1133 |
| 4 | 1313 |
| 5 | 1331 |
| 6 | 3113 |
| 7 | 3131 |
| 8 | 3311 |
| 9 | 111333 |
| 10 | 113133 |
| 11 | 113313 |
| 12 | 113331 |
| 13 | 131133 |
| 14 | 131313 |
| 15 | 131331 |
| 16 | 133113 |
| 17 | 133131 |
| 18 | 133311 |
| 19 | 311133 |
| 20 | 311313 |
| 21 | 311331 |
| 22 | 313113 |
| 23 | 313131 |
| 24 | 313311 |
| 25 | 331113 |
| 26 | 331131 |
| 27 | 331311 |
| 28 | 333111 |
[13,31,1133,1313,1331,3113,3131,3311,111333, 113133,113313,113331,131133,131313,131331,133113, 133131,133311,311133,311313,311331,313113,313131, 313311,331113,331131,331311,333111] |