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 | 13 |
| 2 | 223 |
| 3 | 2333 |
| 4 | 44449 |
| 5 | 555557 |
| 6 | 16666669 |
| 7 | 77767777 |
| 8 | 888888883 |
| 9 | 9199999999 |