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 | 0 |
| 3 | 513 |
| 4 | 281474976378880 |
| 5 | 752316384526264005099991383822237233803945956334136013765601092018187046026142190625 |