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 | 20 |
| 3 | 272 |
| 4 | 65792 |
| 5 | 2901600 |
| 6 | 4596800 |
| 7 | 29016000 |
| 8 | 4295032832 |
| 9 | 5789534400 |
| 10 | 49085337600 |
| 11 | 585248256000 |
| 12 | 960935040000 |