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 | 2 |
| 3 | 52 |
| 4 | 142090700 |
| 5 | 17844701940501123640681816160 |
| 6 | 59757436204078657410908164193971330396709572693816353610758085074676243846093824 |