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 | 9 |
| 2 | 99 |
| 3 | 9009 |
| 4 | 909909 |
| 5 | 9009009009 |
| 6 | 90099099099009 |
| 7 | 90009090099009090009 |
| 8 | 9000009009009009009009000009 |
| 9 | 90000090099090099099099009099009000009 |