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 | 7 |
| 2 | 9 |
| 3 | 49 |
| 4 | 111 |
| 5 | 1090909 |
| 6 | 28571427 |
| 7 | 111111111 |
| 8 | 3333333327 |
| 9 | 25641025641 |
| 10 | 10576923076923 |
| 11 | 59090909090909 |
| 12 | 2631578947368421 |
| 13 | 4827586206896549 |
| 14 | 8947368421052631 |
| 15 | 18644067796610169 |
| 16 | 111111111111111111 |
| 17 | 812499999999999999 |
| 18 | 1889250814332247557 |
| 19 | 9189189189189189189 |