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 | 2 |
| 2 | 4 |
| 3 | 10 |
| 4 | 36 |
| 5 | 168 |
| 6 | 1008 |
| 7 | 7056 |
| 8 | 56448 |
| 9 | 470400 |
| 10 | 4704000 |
| 11 | 51528960 |
| 12 | 618347520 |
| 13 | 7740902400 |
| 14 | 108372633600 |