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) |
|---|---|
| 0 | 11 |
| 1 | 5 |
| 2 | 11551 |
| 3 | 15551 |
| 4 | 1551551 |
| 5 | 15551551 |
| 6 | 1155555151 |
| 7 | 1555551551 |
| 8 | 11555555551 |
| 9 | 1155155555551 |
| 10 | 555555515551 |
| 11 | 555555555551 |
| 12 | 5555555555551 |
| 13 | 555155555555551 |
| 14 | 51555555551555551 |
| 15 | 51555555555555551 |
| 16 | 1155555555555555551 |
| 17 | 15551555555555555551 |
| 18 | 1155515555555555555551 |