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 | 24 |
| 5 | 120 |
| 6 | 720 |
| 7 | 4800 |
| 8 | 34752 |
| 9 | 280512 |
| 10 | 2528256 |
| 11 | 25282560 |
| 12 | 278323200 |
| 13 | 3242649600 |
| 14 | 40330371072 |
| 15 | 536528954880 |
| 16 | 7633092132864 |