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 | 10 |
| 2 | 19 |
| 3 | 109 |
| 4 | 199 |
| 5 | 1099 |
| 6 | 1999 |
| 7 | 10999 |
| 8 | 19999 |
| 9 | 109999 |
| 10 | 199999 |
| 11 | 1099999 |
| 12 | 1999999 |
| 13 | 10999999 |
| 14 | 19999999 |
| 15 | 109999999 |
| 16 | 199999999 |
| 17 | 1099999999 |
| 18 | 1999999999 |
| 19 | 10999999999 |
| 20 | 19999999999 |
| 21 | 109999999999 |
| 22 | 199999999999 |
| 23 | 1099999999999 |
| 24 | 1999999999999 |
| 25 | 10999999999999 |
| 26 | 19999999999999 |