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 | 7 |
| 4 | 21 |
| 5 | 60 |
| 6 | 166 |
| 7 | 463 |
| 8 | 1281 |
| 9 | 3521 |
| 10 | 9645 |
| 11 | 26322 |
| 12 | 71606 |
| 13 | 194283 |
| 14 | 525897 |
| 15 | 1420595 |
| 16 | 3830445 |
| 17 | 10311510 |
| 18 | 27718028 |
| 19 | 74410105 |
| 20 | 199519155 |
| 21 | 534400491 |
| 22 | 1429944603 |
| 23 | 3822761742 |
| 24 | 10211093226 |
| 25 | 27254110405 |
| 26 | 72691102131 |
| 27 | 193750155673 |
| 28 | 516100470051 |