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) |
|---|---|
| 3 | 1 |
| 4 | 86 |
| 5 | 2310 |
| 6 | 42960 |
| 7 | 712320 |
| 8 | 11481120 |
| 9 | 186671520 |
| 10 | 3116534400 |
| 11 | 53907638400 |
| 12 | 970417324800 |
| 13 | 18217668268800 |