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) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 48 |
| 3 | 414720 |
| 4 | 270888468480000 |
| 5 | 30900096179361042923520000000000 |
| 6 | 1848494880770448654906901042987600267878400000000000000000000 |