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 | 1 |
| 1 | 0 |
| 2 | 690880 |
| 3 | 1439241216 |
| 4 | 1600259436000 |
| 5 | 1089164637414400 |
| 6 | 497302797675880000 |
| 7 | 162011412870006528000 |
| 8 | 39370123446823781449200 |
| 9 | 7379968237981419286272000 |
| 10 | 1095459180086149609599422400 |