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 | 7 |
| 2 | 9 |
| 3 | 313 |
| 4 | 999 |
| 5 | 31513 |
| 6 | 75357 |
| 7 | 78687 |
| 8 | 90909 |
| 9 | 98289 |
| 10 | 3159513 |
| 11 | 7642467 |
| 12 | 9009009 |
| 13 | 743080347 |
| 14 | 900090009 |
| 15 | 31413131413 |
| 16 | 90000900009 |
| 17 | 97474147479 |
| 18 | 3105075705013 |
| 19 | 9000009000009 |
| 20 | 757082131280757 |
| 21 | 900000090000009 |
| 22 | 907340818043709 |
| 23 | 90000000900000009 |
| 24 | 92269201110296229 |