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 | 109 |
| 2 | 1099 |
| 3 | 10999 |
| 4 | 109999 |
| 5 | 1099999 |
| 6 | 10999999 |
| 7 | 109999999 |
| 8 | 1099999999 |
| 9 | 10999999999 |
| 10 | 109999999999 |
| 11 | 1099999999999 |
| 12 | 10999999999999 |
| 13 | 109999999999999 |
| 14 | 1099999999999999 |
| 15 | 10999999999999999 |
| 16 | 109999999999999999 |
| 17 | 1099999999999999999 |
| 18 | 10999999999999999999 |
| 19 | 109999999999999999999 |