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 | 2 |
| 2 | 23 |
| 3 | 523 |
| 4 | 2357 |
| 5 | 112573 |
| 6 | 11132357 |
| 7 | 1111233757 |
| 8 | 111112337579 |
| 9 | 11111223373597 |
| 10 | 0 |
| 11 | 111111222333357997 |
| 12 | 11111122233333597977 |
| 13 | 1111111222333334579977 |
| 14 | 111111122233333344977597 |
| 15 | 11111112223333334447797759 |
| 16 | 0 |
| 17 | 111111122233333334445557999777 |
| 18 | 0 |
| 19 | 1111111122233333334445556677799779 |