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 | 2 |
| 4 | 4 |
| 5 | 12 |
| 6 | 20 |
| 7 | 54 |
| 8 | 88 |
| 9 | 232 |
| 10 | 986 |
| 11 | 1596 |
| 12 | 6764 |
| 13 | 17710 |
| 14 | 28656 |
| 15 | 75024 |
| 16 | 317810 |
| 17 | 1346268 |
| 18 | 2178308 |
| 19 | 9227464 |
| 20 | 24157816 |
| 21 | 39088168 |
| 22 | 165580140 |
| 23 | 433494436 |
| 24 | 1836311902 |
| 25 | 12586269024 |
| 26 | 32951280098 |
| 27 | 53316291172 |
| 28 | 139583862444 |
| 29 | 225851433716 |