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) |
|---|---|
| 2 | 0 |
| 3 | 1 |
| 4 | 4 |
| 5 | 396 |
| 6 | 553008 |
| 7 | 4701600128 |
| 8 | 1782158930138112 |
| 9 | 3276113857736492040192 |