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 | 0 |
| 2 | -1 |
| 3 | -17280 |
| 4 | 1168415539200 |
| 5 | 980041972344422400000000 |
| 6 | -24517645963803990318633839493120000000000 |
| 7 | -37442952699741306217982755284947059704721771069440000000000000 |