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 | 1 |
| 1 | 11 |
| 2 | 112 |
| 3 | 1122 |
| 4 | 11223 |
| 5 | 112233 |
| 6 | 1122334 |
| 7 | 11223344 |
| 8 | 112233445 |
| 9 | 1122334455 |
| 10 | 11223344556 |
| 11 | 112233445566 |
| 12 | 1122334455667 |
| 13 | 11223344556677 |
| 14 | 112233445566778 |
| 15 | 1122334455667788 |
| 16 | 11223344556677889 |
| 17 | 112233445566778899 |
| 18 | 1122334455667789000 |
| 19 | 11223344556677890010 |
| 20 | 112233445566778900111 |
| 21 | 1122334455667789001121 |