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) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 0 |
| 7 | 720 |
| 8 | 5760 |
| 9 | 51840 |
| 10 | 518400 |
| 11 | 5702400 |
| 12 | 68428800 |
| 13 | 889574400 |
| 14 | 11564467200 |
| 15 | 173467008000 |
| 16 | 2775472128000 |
| 17 | 47183026176000 |
| 18 | 849294471168000 |
| 19 | 16136594952192000 |
| 20 | 322731899043840000 |
| 21 | 6802195410616320000 |
| 22 | 149648299033559040000 |
| 23 | 3441910877771857920000 |