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 | 6 |
| 4 | 6 |
| 5 | 20 |
| 6 | 1200 |
| 7 | 3024000 |
| 8 | 63504000 |
| 9 | 5334336000 |
| 10 | 4779565056000 |
| 11 | 9635603152896000 |
| 12 | 404695332421632000 |
| 13 | 44071321700715724800000 |
| 14 | 7329942225263039348736000000 |