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 | 2 |
| 5 | 4 |
| 6 | 48 |
| 7 | 384 |
| 8 | 2304 |
| 9 | 4608 |
| 10 | 18432 |
| 11 | 552960 |
| 12 | 19906560 |
| 13 | 796262400 |
| 14 | 33443020800 |
| 15 | 66886041600 |
| 16 | 267544166400 |
| 17 | 535088332800 |
| 18 | 32105299968000 |
| 19 | 2118949797888000 |
| 20 | 148326485852160000 |
| 21 | 10679506981355520000 |
| 22 | 833001544545730560000 |
| 23 | 1666003089091461120000 |
| 24 | 146608271840048578560000 |