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 | 4 |
| 2 | 13 |
| 3 | 38 |
| 4 | 111 |
| 5 | 326 |
| 6 | 961 |
| 7 | 2842 |
| 8 | 8425 |
| 9 | 25020 |
| 10 | 74403 |
| 11 | 221488 |
| 12 | 659895 |
| 13 | 1967422 |
| 14 | 5869055 |
| 15 | 17516540 |
| 16 | 52300729 |
| 17 | 156214828 |
| 18 | 466736979 |
| 19 | 1394894672 |
| 20 | 4169810935 |
| 21 | 12467680862 |
| 22 | 37285474803 |
| 23 | 111524444760 |
| 24 | 333633526937 |
| 25 | 998233861836 |