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 | 3 |
| 4 | 5 |
| 5 | 19 |
| 6 | 75 |
| 7 | 305 |
| 8 | 1270 |
| 9 | 5390 |
| 10 | 23236 |
| 11 | 101480 |
| 12 | 448085 |
| 13 | 1997115 |
| 14 | 8973255 |
| 15 | 40602093 |
| 16 | 184853055 |
| 17 | 846206025 |
| 18 | 3892585325 |
| 19 | 17984308775 |
| 20 | 83417287855 |
| 21 | 388297304825 |
| 22 | 1813341109825 |
| 23 | 8493372326675 |
| 24 | 39889629750600 |