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 | 1 |
| 2 | 2 |
| 3 | 12 |
| 4 | 1440 |
| 5 | 7257600 |
| 6 | 4981616640000 |
| 7 | 1190690865178214400000 |
| 8 | 272795714695463271824306995200000 |
| 9 | 157357907118293002525216789633250308915200000000 |