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 | 1 |
| 3 | 6 |
| 4 | 720 |
| 5 | 6652800 |
| 6 | 1693749657600 |
| 7 | 367216146859161600000 |
| 8 | 1888288177044984240734208000000 |
| 9 | 4157567140515322460268246337585152000000000 |