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 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 3 |
| 5 | 6 |
| 6 | 9 |
| 7 | 12 |
| 8 | 21 |
| 9 | 42 |
| 10 | 150 |
| 11 | 195 |
| 12 | 390 |
| 13 | 411 |
| 14 | 1215 |
| 15 | 2754 |
| 16 | 2757 |
| 17 | 3246 |
| 18 | 6186 |
| 19 | 11340 |
| 20 | 12885 |
| 21 | 84708 |
| 22 | 87120 |
| 23 | 191772 |
| 24 | 503919 |
| 25 | 786441 |