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 | 0 |
| 2 | 53 |
| 3 | 0 |
| 4 | 557 |
| 5 | 55511 |
| 6 | 55555555555555555555555555555555555555555555555555555555555555555555513 |
| 7 | 55555517 |
| 8 | 5519 |
| 9 | 523 |
| 10 | 55529 |
| 11 | 5531 |
| 12 | 0 |
| 13 | 541 |
| 14 | 55555543 |
| 15 | 547 |
| 16 | 55555553 |
| 17 | 55555559 |