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 | 1 |
| 3 | 8 |
| 4 | 61 |
| 5 | 5020 |
| 6 | 128541455 |
| 7 | 162924332716605980 |
| 8 | 28783052231699298507846309644849796 |
| 9 | 871295615653899563300996782209332544845605756266650946342214549769447 |