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 | 121 |
| 2 | 1221 |
| 3 | 12221 |
| 4 | 122221 |
| 5 | 1222221 |
| 6 | 12222221 |
| 7 | 122222221 |
| 8 | 1222222221 |
| 9 | 12222222221 |
| 10 | 122222222221 |
| 11 | 1222222222221 |
| 12 | 12222222222221 |
| 13 | 122222222222221 |
| 14 | 1222222222222221 |
| 15 | 12222222222222221 |
| 16 | 122222222222222221 |
| 17 | 1222222222222222221 |
| 18 | 12222222222222222221 |
| 19 | 122222222222222222221 |