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| n | a(n) |
|---|---|
| 2 | 31 |
| 3 | 251 |
| 4 | 4231 |
| 5 | 20231 |
| 6 | 420221 |
| 7 | 2020231 |
| 8 | 42020351 |
| 9 | 402020251 |
| 10 | 4002020251 |
| 11 | 20002020721 |
| 12 | 420002020271 |
| 13 | 2020002020251 |
| 14 | 42020002020551 |
| 15 | 402020002020521 |
| 16 | 4002020002020221 |
| 17 | 20002020002020531 |
| 18 | 420002020002020231 |
[31,251,4231,20231,420221,2020231,42020351, 402020251,4002020251,20002020721,420002020271, 2020002020251,42020002020551,402020002020521, 4002020002020221,20002020002020531, 420002020002020231] |