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 | 0 |
| 2 | 22 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 0 |
| 7 | 0 |
| 8 | 31331819 |
| 9 | 0 |
| 10 | 3122331819 |
| 11 | 0 |
| 12 | 0 |
| 13 | 0 |
| 14 | 41322324171819 |
| 15 | 0 |
| 16 | 5132232516171819 |
| 17 | 0 |
| 18 | 613223141526171819 |
| 19 | 1111213141516171819 |
| 20 | 10713223141516271819 |
| 21 | 101112213141516171819 |