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 | 720 |
| 2 | 190800 |
| 3 | 15321600 |
| 4 | 283046400 |
| 5 | 812851200 |
| 6 | 812851200 |
| 7 | 61479419904000 |