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 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 6 |
| 5 | 27 |
| 6 | 111 |
| 7 | 441 |
| 8 | 1728 |
| 9 | 6733 |
| 10 | 26181 |
| 11 | 101763 |
| 12 | 395693 |
| 13 | 1539759 |
| 14 | 5997159 |
| 15 | 23381019 |
| 16 | 91244934 |
| 17 | 356427459 |
| 18 | 1393585779 |
| 19 | 5453514729 |
| 20 | 21358883439 |
| 21 | 83718027429 |
| 22 | 328380697629 |
| 23 | 1288947615849 |
| 24 | 5062603365999 |
| 25 | 19896501060225 |
| 26 | 78239857877649 |
| 27 | 307831771279549 |
| 28 | 1211767933187601 |