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 | 0 |
| 1 | 2 |
| 2 | 24883200 |
| 3 | 6658606584104736522240000000 |
| 4 | 69113789582492712943486800506462734562847413501952000000000000000 |