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 | 1 |
| 3 | 4 |
| 4 | 18 |
| 5 | 80 |
| 6 | 367 |
| 7 | 1708 |
| 8 | 8122 |
| 9 | 39204 |
| 10 | 191963 |
| 11 | 950984 |
| 12 | 4759626 |
| 13 | 24030736 |
| 14 | 122258314 |
| 15 | 626162464 |
| 16 | 3225926450 |
| 17 | 16706775984 |
| 18 | 86928097451 |
| 19 | 454203897192 |
| 20 | 2382255252398 |
| 21 | 12537764465072 |
| 22 | 66193294753768 |
| 23 | 350472816969976 |
| 24 | 1860542261745782 |
| 25 | 9901018433270812 |