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) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 24 |
| 5 | 66 |
| 6 | 187 |
| 7 | 529 |
| 8 | 1506 |
| 9 | 4312 |
| 10 | 12394 |
| 11 | 35742 |
| 12 | 103377 |
| 13 | 299745 |
| 14 | 871011 |
| 15 | 2535873 |
| 16 | 7395522 |
| 17 | 21600720 |
| 18 | 63176964 |
| 19 | 185004852 |
| 20 | 542365407 |
| 21 | 1591631595 |
| 22 | 4675170690 |
| 23 | 13744341390 |
| 24 | 40438307599 |
| 25 | 119063564395 |
| 26 | 350799321531 |