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 | 120 |
| 2 | 13305600 |
| 3 | 29640619008000 |
| 4 | 478741050720092160000 |
| 5 | 34111736086958726676480000000 |
| 6 | 7973107998754741458076119859200000000 |
| 7 | 5019026197962676820927435579005599744000000000 |