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 | 9 |
| 2 | 15 |
| 3 | 27 |
| 4 | 57 |
| 5 | 81 |
| 6 | 177 |
| 7 | 243 |
| 8 | 393 |
| 9 | 579 |
| 10 | 729 |
| 11 | 849 |
| 12 | 1257 |
| 13 | 2187 |
| 14 | 4197 |
| 15 | 4143 |
| 16 | 5853 |
| 17 | 6561 |
| 18 | 17817 |
| 19 | 17781 |
| 20 | 19683 |
| 21 | 56157 |
| 22 | 59049 |
| 23 | 104289 |
| 24 | 104277 |
| 25 | 154509 |