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 | 12 |
| 2 | 192 |
| 3 | 1992 |
| 4 | 19992 |
| 5 | 199992 |
| 6 | 1999992 |
| 7 | 19999992 |
| 8 | 199999992 |
| 9 | 1999999992 |
| 10 | 19999999992 |
| 11 | 199999999992 |
| 12 | 1999999999992 |
| 13 | 19999999999992 |
| 14 | 199999999999992 |
| 15 | 1999999999999992 |
| 16 | 19999999999999992 |
| 17 | 199999999999999992 |
| 18 | 1999999999999999992 |
| 19 | 19999999999999999992 |
| 20 | 199999999999999999992 |