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 | 1 |
| 1 | 91 |
| 2 | 9091 |
| 3 | 909091 |
| 4 | 90909091 |
| 5 | 9090909091 |
| 6 | 909090909091 |
| 7 | 90909090909091 |
| 8 | 9090909090909091 |
| 9 | 909090909090909091 |
| 10 | 90909090909090909091 |
| 11 | 9090909090909090909091 |
| 12 | 909090909090909090909091 |