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 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 11 |
| 5 | 33 |
| 6 | 99 |
| 7 | 101 |
| 8 | 303 |
| 9 | 909 |
| 10 | 1111 |
| 11 | 3333 |
| 12 | 9999 |