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) |
|---|---|
| 7 | 4 |
| 8 | 28 |
| 9 | 176 |
| 10 | 950 |
| 11 | 4908 |
| 12 | 24402 |
| 13 | 119240 |
| 14 | 575348 |
| 15 | 2757460 |
| 16 | 13157752 |
| 17 | 62638788 |
| 18 | 297832008 |
| 19 | 1415550920 |
| 20 | 6728600060 |
| 21 | 31998023632 |
| 22 | 152271569872 |
| 23 | 725231959452 |
| 24 | 3457304575812 |
| 25 | 16497751608120 |
| 26 | 78804354881238 |
| 27 | 376806016649964 |
| 28 | 1803539487096138 |
| 29 | 8641075826669256 |
| 30 | 41441524062045660 |