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) |
|---|---|
| 2 | 0 |
| 3 | 6 |
| 4 | 58 |
| 5 | 328 |
| 6 | 1452 |
| 7 | 5610 |
| 8 | 19950 |
| 9 | 67260 |
| 10 | 218848 |
| 11 | 695038 |
| 12 | 2170626 |
| 13 | 6699696 |
| 14 | 20507988 |
| 15 | 62407890 |
| 16 | 189123286 |
| 17 | 571432036 |
| 18 | 1722945672 |
| 19 | 5187185766 |
| 20 | 15600353130 |
| 21 | 46882846680 |
| 22 | 140820504700 |
| 23 | 422822222266 |
| 24 | 1269221639358 |
| 25 | 3809241974028 |
| 26 | 11431014253872 |
| 27 | 34299887862990 |