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) |
|---|---|
| 3 | 1 |
| 4 | -6 |
| 5 | 85 |
| 6 | -1350 |
| 7 | 26341 |
| 8 | -603246 |
| 9 | 15887845 |
| 10 | -473148150 |
| 11 | 15723174181 |
| 12 | -576826897086 |
| 13 | 23157022930405 |
| 14 | -1009818279438150 |
| 15 | 47533643556874021 |
| 16 | -2402218856253008526 |
| 17 | 129730266330534913765 |
| 18 | -7455932648513351731350 |
| 19 | 454377365410347843373861 |