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 | 3 |
| 3 | 40 |
| 4 | 1260 |
| 5 | 7983360 |
| 6 | 1037836800 |
| 7 | 50812489728000 |
| 8 | 15205637551104000 |
| 9 | 2872446304320552960000 |
| 10 | 884176199373970195454361600000 |
| 11 | 747530786743447528884142080000000 |