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 | 1 |
| 2 | 2 |
| 3 | 1440 |
| 4 | 689762304000 |
| 5 | 1678124094566146045378560000000 |
| 6 | 445127215203413988036981576746329306509322538188800000000000000 |