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 | 1 |
| 3 | 1 |
| 4 | 8 |
| 5 | 405 |
| 6 | 2520 |
| 7 | 4320 |
| 8 | 32781000 |
| 9 | 256556160 |
| 10 | 10590199200 |
| 11 | 2225341641600 |
| 12 | 28746722188800 |