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 | 15 |
| 3 | 27 |
| 4 | 51 |
| 5 | 147 |
| 6 | 243 |
| 7 | 267 |
| 8 | 347 |
| 9 | 471 |
| 10 | 747 |
| 11 | 2163 |
| 12 | 3087 |
| 13 | 5355 |
| 14 | 6539 |
| 15 | 7311 |
| 16 | 99231 |
| 17 | 824451 |
| 18 | 1388355 |
| 19 | 1990299 |
| 20 | 8636199 |