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) |
|---|---|
| 2 | -1 |
| 3 | -1 |
| 4 | -19 |
| 5 | -593 |
| 6 | -23877 |
| 7 | -4496245 |
| 8 | -1588528613 |
| 9 | -12927125815211 |