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 | 4 |
| 2 | 24 |
| 3 | 84672 |
| 4 | 1852200 |
| 5 | 829785600 |
| 6 | 20910597120 |
| 7 | 92215733299200 |
| 8 | 1239789303244800000 |
| 9 | 887165996513213819259682435576627200000000 |