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 | 0 |
| 1 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 33 |
| 5 | 107 |
| 6 | 333 |
| 7 | 1036 |
| 8 | 3153 |
| 9 | 9583 |
| 10 | 29010 |
| 11 | 87557 |
| 12 | 263679 |
| 13 | 793061 |
| 14 | 2383280 |
| 15 | 7158069 |
| 16 | 21490605 |
| 17 | 64504548 |
| 18 | 193579176 |
| 19 | 580868607 |
| 20 | 1742867913 |
| 21 | 5229128045 |
| 22 | 15688432647 |
| 23 | 47067395121 |
| 24 | 141206379612 |
| 25 | 423627527495 |
| 26 | 1270899359726 |
| 27 | 3812731633623 |
| 28 | 11438262009764 |