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 | 2 |
| 2 | 4181 |
| 3 | 24157817 |
| 4 | 83621143489848422977 |
| 5 | 322615043836854783580186309282650000354271239929 |