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) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 11 |
| 4 | 36 |
| 5 | 127 |
| 6 | 405 |
| 7 | 1409 |
| 8 | 4561 |
| 9 | 15559 |
| 10 | 50294 |
| 11 | 169537 |
| 12 | 551001 |
| 13 | 1835073 |
| 14 | 5947516 |
| 15 | 19717181 |
| 16 | 63697526 |
| 17 | 209422033 |
| 18 | 676831026 |
| 19 | 2208923853 |
| 20 | 7112963260 |
| 21 | 23127536979 |
| 22 | 74225466424 |
| 23 | 239962004807 |
| 24 | 768695233371 |
| 25 | 2473092566267 |
| 26 | 7896286237030 |
| 27 | 25316008015581 |
| 28 | 80572339461372 |