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 | 5 |
| 2 | 15 |
| 3 | 135 |
| 4 | 175 |
| 5 | 315 |
| 6 | 735 |
| 7 | 1395 |
| 8 | 1935 |
| 9 | 3195 |
| 10 | 3915 |
| 11 | 9135 |
| 12 | 9315 |