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 | 3 |
| 2 | 33 |
| 3 | 333 |
| 4 | 3333 |
| 5 | 33433 |
| 6 | 334433 |
| 7 | 3344433 |
| 8 | 33433433 |
| 9 | 334444433 |
| 10 | 3344444433 |
| 11 | 33434443433 |
| 12 | 334445544433 |
| 13 | 3344455544433 |
| 14 | 33434000043433 |
| 15 | 334444444444433 |
| 16 | 3344444334444433 |
| 17 | 33434400000443433 |
| 18 | 334445433334544433 |
| 19 | 3344454322234544433 |
| 20 | 33434050022005043433 |
| 21 | 3344444433333344444433 |