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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 7 |
| 3 | 227 |
| 4 | 277 |
| 5 | 727 |
| 6 | 2777 |
| 7 | 7727 |
| 8 | 22277 |
| 9 | 22727 |
| 10 | 22777 |
| 11 | 27277 |
| 12 | 72227 |
| 13 | 72277 |
| 14 | 72727 |
| 15 | 272227 |
| 16 | 272777 |
| 17 | 727777 |
| 18 | 777277 |
| 19 | 2227727 |
| 20 | 2227777 |
| 21 | 2272727 |
| 22 | 2277727 |
| 23 | 2727727 |
| 24 | 2772227 |
| 25 | 7272227 |
| 26 | 7722277 |
| 27 | 7727777 |
| 28 | 7772777 |
| 29 | 7777727 |
| 30 | 22227277 |
| 31 | 22272277 |
[2,7,227,277,727,2777,7727,22277,22727,22777, 27277,72227,72277,72727,272227,272777,727777, 777277,2227727,2227777,2272727,2277727,2727727, 2772227,7272227,7722277,7727777,7772777,7777727, 22227277,22272277] |