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 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 9 |
| 5 | 21 |
| 6 | 27 |
| 7 | 63 |
| 8 | 81 |
| 9 | 189 |
| 10 | 243 |
| 11 | 567 |
| 12 | 1701 |