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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 21 |
| 3 | 31 |
| 4 | 421 |
| 5 | 521 |
| 6 | 631 |
| 7 | 731 |
| 8 | 8421 |
| 9 | 9421 |
| 10 | 10521 |
| 11 | 11521 |
| 12 | 12631 |
| 13 | 13631 |
| 14 | 14731 |
| 15 | 15731 |
| 16 | 168421 |
| 17 | 178421 |
| 18 | 189421 |
| 19 | 199421 |
| 20 | 2010521 |
| 21 | 2110521 |
| 22 | 2211521 |
| 23 | 2311521 |
| 24 | 2412631 |
| 25 | 2512631 |
| 26 | 2613631 |
| 27 | 2713631 |
| 28 | 2814731 |
| 29 | 2914731 |
| 30 | 3015731 |
| 31 | 3115731 |
| 32 | 32168421 |
[1,21,31,421,521,631,731,8421,9421,10521,11521, 12631,13631,14731,15731,168421,178421,189421, 199421,2010521,2110521,2211521,2311521,2412631, 2512631,2613631,2713631,2814731,2914731,3015731, 3115731,32168421] |