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) |
|---|---|
| 0 | 1 |
| 1 | 6 |
| 2 | 40 |
| 3 | 5040 |
| 4 | 362880 |
| 5 | 13305600 |
| 6 | 6227020800 |
| 7 | 1307674368000 |
| 8 | 513257472000 |
| 9 | 121645100408832000 |
| 10 | 51090942171709440000 |
| 11 | 8617338912961658880000 |
| 12 | 15511210043330985984000000 |
| 13 | 10888869450418352160768000000 |
| 14 | 2947253997913233984847872000000 |
| 15 | 1174691236311131831103651840000000 |