| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 5 |
| 3 | 7 |
| 4 | 227 |
| 5 | 257 |
| 6 | 277 |
| 7 | 557 |
| 8 | 577 |
| 9 | 727 |
| 10 | 757 |
| 11 | 2557 |
| 12 | 2777 |
| 13 | 5227 |
| 14 | 5527 |
| 15 | 5557 |
| 16 | 7577 |
| 17 | 7727 |
| 18 | 7757 |
| 19 | 22277 |
| 20 | 22727 |
| 21 | 22777 |
| 22 | 25577 |
| 23 | 27277 |
| 24 | 27527 |
| 25 | 52727 |
| 26 | 52757 |
| 27 | 57527 |
| 28 | 57557 |
| 29 | 57727 |
| 30 | 72227 |
| 31 | 72277 |
| 32 | 72577 |
| 33 | 72727 |
| 34 | 75227 |
| 35 | 75277 |
| 36 | 75527 |
| 37 | 75557 |
| 38 | 75577 |
| 39 | 77527 |
| 40 | 77557 |
| 41 | 222527 |
| 42 | 222557 |
[2,5,7,227,257,277,557,577,727,757,2557,2777,5227, 5527,5557,7577,7727,7757,22277,22727,22777,25577, 27277,27527,52727,52757,57527,57557,57727,72227, 72277,72577,72727,75227,75277,75527,75557,75577, 77527,77557,222527,222557] |