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 | 0 |
| 2 | 3 |
| 3 | 60 |
| 4 | 2520 |
| 5 | 181440 |
| 6 | 19958400 |
| 7 | 3113510400 |
| 8 | 653837184000 |
| 9 | 177843714048000 |
| 10 | 60822550204416000 |
| 11 | 25545471085854720000 |
| 12 | 12926008369442488320000 |
| 13 | 7755605021665492992000000 |
| 14 | 5444434725209176080384000000 |
| 15 | 4420880996869850977271808000000 |