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 | -10 |
| 1 | -11 |
| 2 | -9 |
| 3 | 91 |
| 4 | 101 |
| 5 | 9091 |
| 6 | 111 |
| 7 | 909091 |
| 8 | 10001 |
| 9 | 999001 |
| 10 | 11111 |
| 11 | 9090909091 |
| 12 | 9901 |
| 13 | 909090909091 |
| 14 | 1111111 |
| 15 | 109889011 |
| 16 | 100000001 |
| 17 | 9090909090909091 |
| 18 | 1001001 |
| 19 | 909090909090909091 |
| 20 | 99009901 |
| 21 | 1098900989011 |
| 22 | 11111111111 |