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 | 7 |
| 5 | 37 |
| 6 | 175 |
| 7 | 778 |
| 8 | 3325 |
| 9 | 13837 |
| 10 | 56524 |
| 11 | 227866 |
| 12 | 909832 |
| 13 | 3607294 |
| 14 | 14227447 |
| 15 | 55894252 |
| 16 | 218937532 |
| 17 | 855650749 |
| 18 | 3338323915 |
| 19 | 13007422705 |
| 20 | 50631143323 |
| 21 | 196928737582 |
| 22 | 765495534433 |
| 23 | 2974251390529 |
| 24 | 11552064922624 |
| 25 | 44856304154086 |