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) |
|---|---|
| 4 | 0 |
| 5 | 60 |
| 6 | 720 |
| 7 | 7560 |
| 8 | 80640 |
| 9 | 907200 |
| 10 | 10886400 |
| 11 | 139708800 |
| 12 | 1916006400 |
| 13 | 28021593600 |
| 14 | 435891456000 |
| 15 | 7192209024000 |
| 16 | 125536739328000 |
| 17 | 2311968282624000 |
| 18 | 44816615940096000 |
| 19 | 912338253066240000 |
| 20 | 19463216065413120000 |
| 21 | 434273008459530240000 |
| 22 | 10116006549998469120000 |