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 | 6 |
| 2 | 720 |
| 3 | 31449600 |
| 4 | 444733651353600 |
| 5 | 10070314878246926155776000 |
| 6 | 614972203951464612786852376432607232000 |