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 | 3 |
| 2 | 7 |
| 3 | 7 |
| 4 | 19 |
| 5 | 19 |
| 6 | 139 |
| 7 | 151 |
| 8 | 211 |
| 9 | 211 |
| 10 | 211 |
| 11 | 421 |
| 12 | 2311 |
| 13 | 2311 |
| 14 | 92401 |
| 15 | 120121 |
| 16 | 120121 |
| 17 | 180181 |
| 18 | 2312311 |