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) |
|---|---|
| 3 | 1 |
| 4 | 1 |
| 5 | 1 |
| 6 | 1 |
| 7 | 1 |
| 8 | 2 |
| 9 | 4 |
| 10 | 10 |
| 11 | 25 |
| 12 | 87 |
| 13 | 313 |
| 14 | 1357 |
| 15 | 6244 |
| 16 | 30926 |
| 17 | 158428 |
| 18 | 836749 |
| 19 | 4504607 |
| 20 | 24649284 |
| 21 | 136610879 |
| 22 | 765598927 |
| 23 | 4332047595 |
| 24 | 24724362117 |
| 25 | 142205424580 |
| 26 | 823687567019 |
| 27 | 4801749063379 |