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) |
|---|---|
| 2 | 1 |
| 3 | 3 |
| 4 | 9 |
| 5 | 28 |
| 6 | 84 |
| 7 | 246 |
| 8 | 714 |
| 9 | 2059 |
| 10 | 5917 |
| 11 | 16971 |
| 12 | 48633 |
| 13 | 139333 |
| 14 | 399267 |
| 15 | 1144669 |
| 16 | 3283839 |
| 17 | 9427981 |
| 18 | 27090715 |
| 19 | 77911897 |
| 20 | 224272499 |
| 21 | 646157234 |
| 22 | 1863317958 |
| 23 | 5377939756 |
| 24 | 15535195892 |
| 25 | 44913790501 |
| 26 | 129955421387 |
| 27 | 376313609029 |