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) |
|---|---|
| 1 | 1 |
| 2 | 8 |
| 3 | 108 |
| 4 | 576 |
| 5 | 18000 |
| 6 | 21600 |
| 7 | 1234800 |
| 8 | 5644800 |
| 9 | 57153600 |
| 10 | 12700800 |
| 11 | 1690476480 |
| 12 | 1844156160 |
| 13 | 337634256960 |
| 14 | 363606122880 |
| 15 | 1947889944000 |
| 16 | 8310997094400 |
| 17 | 2551995545299200 |
| 18 | 2702112930316800 |
| 19 | 1029655143835718400 |
| 20 | 216769503965414400 |
| 21 | 4645060799258880 |