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 | 9 |
| 2 | 18 |
| 3 | 108 |
| 4 | 198 |
| 5 | 1098 |
| 6 | 1998 |
| 7 | 10998 |
| 8 | 19998 |
| 9 | 109998 |
| 10 | 199998 |
| 11 | 1099998 |
| 12 | 1999998 |
| 13 | 10999998 |
| 14 | 19999998 |
| 15 | 109999998 |
| 16 | 199999998 |
| 17 | 1099999998 |
| 18 | 1999999998 |
| 19 | 10999999998 |
| 20 | 19999999998 |
| 21 | 109999999998 |
| 22 | 199999999998 |
| 23 | 1099999999998 |
| 24 | 1999999999998 |
| 25 | 10999999999998 |