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 | 1223 |
| 3 | 3343 |
| 4 | 1044443 |
| 5 | 1555553 |
| 6 | 166616663 |
| 7 | 172777777 |
| 8 | 15888888887 |
| 9 | 9299999999 |