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 | 2 |
| 2 | 23 |
| 3 | 29 |
| 4 | 211 |
| 5 | 233 |
| 6 | 277 |
| 7 | 2111 |
| 8 | 2333 |
| 9 | 2777 |
| 10 | 2999 |
| 11 | 23333 |
| 12 | 2999999 |
| 13 | 29999999 |
| 14 | 2777777777 |
| 15 | 23333333333 |
| 16 | 2111111111111 |
| 17 | 2777777777777777 |
| 18 | 23333333333333333 |
| 19 | 2111111111111111111 |
| 20 | 2777777777777777777 |