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 | 11 |
| 1 | 23 |
| 2 | 149 |
| 3 | 389 |
| 4 | 6389 |
| 5 | 38669 |
| 6 | 89899 |
| 7 | 688999 |
| 8 | 4998989 |
| 9 | 46998899 |
| 10 | 288989999 |
| 11 | 2688989999 |
| 12 | 8889899999 |
| 13 | 68898899999 |
| 14 | 1488988999999 |
| 15 | 3888998899999 |
| 16 | 128889898999999 |
| 17 | 348889899899999 |
| 18 | 1888888999999999 |
| 19 | 16888888999999999 |