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) |
|---|---|
| 3 | 1 |
| 4 | 6 |
| 5 | 29 |
| 6 | 124 |
| 7 | 499 |
| 8 | 1933 |
| 9 | 7307 |
| 10 | 27166 |
| 11 | 99841 |
| 12 | 363980 |
| 13 | 1319404 |
| 14 | 4763927 |
| 15 | 17155264 |
| 16 | 61672791 |
| 17 | 221499015 |
| 18 | 795198010 |
| 19 | 2854898575 |
| 20 | 10253237150 |
| 21 | 36846414395 |
| 22 | 132518215788 |
| 23 | 477049025009 |
| 24 | 1719101735260 |
| 25 | 6201858101192 |
| 26 | 22399768386170 |
| 27 | 80998670324341 |
| 28 | 293244129636085 |