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 | 29999999 |
| 2 | 39899999 |
| 3 | 39999899 |
| 4 | 48999989 |
| 5 | 49898999 |
| 6 | 49899989 |
| 7 | 49979999 |
| 8 | 49997999 |
| 9 | 57899999 |
| 10 | 57998999 |
| 11 | 57999899 |
| 12 | 58899989 |
| 13 | 58989899 |
| 14 | 58998899 |
| 15 | 59879999 |
| 16 | 59898899 |
| 17 | 59898989 |
| 18 | 59979989 |
| 19 | 59987999 |
| 20 | 59988989 |
| 21 | 59999879 |