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) |
|---|---|
| 1 | 0 |
| 2 | 4 |
| 3 | 30 |
| 4 | 58081 |
| 5 | 78633756 |
| 6 | 4919350997521 |
| 7 | 720107530988047980 |
| 8 | 2283974100099963226425600 |