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 | 0 |
| 6 | 1 |
| 7 | 3 |
| 8 | 12 |
| 9 | 52 |
| 10 | 241 |
| 11 | 1173 |
| 12 | 5929 |
| 13 | 30880 |
| 14 | 164796 |
| 15 | 897380 |
| 16 | 4970296 |
| 17 | 27930828 |
| 18 | 158935761 |
| 19 | 914325657 |
| 20 | 5310702819 |
| 21 | 31110146416 |
| 22 | 183634501753 |
| 23 | 1091371140915 |
| 24 | 6526333259312 |
| 25 | 39246152584304 |
| 26 | 237214507388796 |
| 27 | 1440503185260748 |