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 | 2 |
| 1 | 41 |
| 2 | 443 |
| 3 | 4441 |
| 4 | 44449 |
| 5 | 444443 |
| 6 | 24444443 |
| 7 | 424444441 |
| 8 | 444444443 |
| 9 | 4444444447 |
| 10 | 44444444441 |
| 11 | 444444444443 |
| 12 | 14444444444449 |
| 13 | 440444444444441 |
| 14 | 2444444444444447 |
| 15 | 44044444444444441 |
| 16 | 424444444444444447 |
| 17 | 4344444444444444449 |
| 18 | 42444444444444444443 |
| 19 | 44444444444444444447 |