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 | 0 |
| 1 | 27 |
| 2 | 297 |
| 3 | 2997 |
| 4 | 29997 |
| 5 | 299997 |
| 6 | 2999997 |
| 7 | 29999997 |
| 8 | 299999997 |
| 9 | 2999999997 |
| 10 | 29999999997 |
| 11 | 299999999997 |
| 12 | 2999999999997 |
| 13 | 29999999999997 |
| 14 | 299999999999997 |
| 15 | 2999999999999997 |
| 16 | 29999999999999997 |
| 17 | 299999999999999997 |
| 18 | 2999999999999999997 |
| 19 | 29999999999999999997 |
| 20 | 299999999999999999997 |