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 | 0 |
| 1 | 1 |
| 2 | 4 |
| 3 | 56 |
| 4 | 1728 |
| 5 | -45696 |
| 6 | -159401472 |
| 7 | 387212983296 |
| 8 | 14722642769657856 |
| 9 | -783395638188945997824 |
| 10 | -571756408840959817330851840 |
| 11 | 603349161280921866200339538247680 |
| 12 | 8390141848229920894318007084122311229440 |