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) |
|---|---|
| 6 | 1 |
| 7 | 42 |
| 8 | 1176 |
| 9 | 28224 |
| 10 | 635040 |
| 11 | 13970880 |
| 12 | 307359360 |
| 13 | 6849722880 |
| 14 | 155831195520 |
| 15 | 3636061228800 |
| 16 | 87265469491200 |
| 17 | 2157837063782400 |
| 18 | 55024845126451200 |
| 19 | 1447576694865100800 |
| 20 | 39291367432052736000 |
| 21 | 1100158288097476608000 |
| 22 | 31767070568814637056000 |