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) |
|---|---|
| 2 | 288 |
| 3 | 28200960 |
| 4 | 29136487207403520 |
| 5 | 1903816047972624930994913280000 |