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) |
|---|---|
| 4 | 1 |
| 5 | 2 |
| 6 | 10 |
| 7 | 40 |
| 8 | 185 |
| 9 | 828 |
| 10 | 3805 |
| 11 | 17411 |
| 12 | 80177 |
| 13 | 369675 |
| 14 | 1710173 |
| 15 | 7931011 |
| 16 | 36884730 |
| 17 | 171987194 |
| 18 | 804027444 |
| 19 | 3767994408 |
| 20 | 17699839325 |
| 21 | 83328339997 |
| 22 | 393123808821 |
| 23 | 1858351499207 |
| 24 | 8801160980038 |
| 25 | 41756069328689 |
| 26 | 198437460900302 |
| 27 | 944521149228740 |
| 28 | 4502419787519360 |