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 | 15 |
| 4 | 35 |
| 5 | 103 |
| 6 | 343 |
| 7 | 979 |
| 8 | 2915 |
| 9 | 8935 |
| 10 | 26559 |
| 11 | 79499 |
| 12 | 239547 |
| 13 | 717455 |
| 14 | 2151095 |
| 15 | 6459027 |
| 16 | 19371507 |
| 17 | 58106071 |
| 18 | 174349295 |
| 19 | 523022555 |
| 20 | 1569013931 |
| 21 | 4707208351 |
| 22 | 14121515303 |
| 23 | 42364215075 |
| 24 | 127093528675 |
| 25 | 381280144743 |
| 26 | 1143838446943 |
| 27 | 3431519977579 |
| 28 | 10294558387995 |