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 | 2 |
| 3 | 6 |
| 4 | 21 |
| 5 | 75 |
| 6 | 268 |
| 7 | 958 |
| 8 | 3425 |
| 9 | 12245 |
| 10 | 43778 |
| 11 | 156514 |
| 12 | 559565 |
| 13 | 2000543 |
| 14 | 7152292 |
| 15 | 25570698 |
| 16 | 91419729 |
| 17 | 326841561 |
| 18 | 1168515890 |
| 19 | 4177649198 |
| 20 | 14935828405 |
| 21 | 53398205443 |
| 22 | 190907947468 |
| 23 | 682529386598 |
| 24 | 2440162233937 |
| 25 | 8724007852045 |
| 26 | 31189857766034 |
| 27 | 111509210441322 |
| 28 | 398664979703373 |