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 | 1 |
| 2 | 5 |
| 3 | 105 |
| 4 | 8925 |
| 5 | 3043425 |
| 6 | 4154275125 |
| 7 | 22686496457625 |
| 8 | 495586515116818125 |
| 9 | 43304845277422684580625 |
| 10 | 15136126045591163828042953125 |
| 11 | 21161832960467051739150680807015625 |
| 12 | 118345540457280742481284963098558216328125 |
| 13 | 2647344887069536899904944217513732945696167890625 |