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 | 449 |
| 2 | 499 |
| 3 | 4999 |
| 4 | 9949 |
| 5 | 44449 |
| 6 | 49499 |
| 7 | 49999 |
| 8 | 94949 |
| 9 | 94999 |
| 10 | 444449 |
| 11 | 994949 |
| 12 | 999499 |
| 13 | 4444949 |
| 14 | 4449449 |
| 15 | 4944949 |
| 16 | 4949449 |
| 17 | 4999949 |
| 18 | 4999999 |
| 19 | 9444949 |
| 20 | 9494999 |
| 21 | 9944449 |
| 22 | 9994499 |
| 23 | 44444999 |
| 24 | 44499449 |
| 25 | 44944499 |
| 26 | 44994949 |
| 27 | 49444949 |
| 28 | 49444999 |
| 29 | 49494499 |