This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 1 | 5 |
| 2 | 0 |
| 3 | 557 |
| 4 | 5557 |
| 5 | 57557 |
| 6 | 555557 |
| 7 | 5555777 |
| 8 | 55555777 |
| 9 | 555557557 |
| 10 | 5555555557 |
| 11 | 55555555777 |
| 12 | 555555575557 |
| 13 | 5555555757757 |
| 14 | 55555555575757 |
| 15 | 555555555555557 |
| 16 | 5555555555557577 |
| 17 | 55555555555777777 |
| 18 | 555555555557557757 |
| 19 | 5555555555555557577 |
| 20 | 55555555555575755777 |