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 | -1 |
| 2 | 2 |
| 3 | -9 |
| 4 | 74 |
| 5 | -955 |
| 6 | 17744 |
| 7 | -448077 |
| 8 | 14751974 |
| 9 | -613569711 |
| 10 | 31452344252 |
| 11 | -1947832408225 |
| 12 | 143356013568338 |
| 13 | -12366684481981635 |
| 14 | 1235842203066704648 |
| 15 | -141628365906835323573 |
| 16 | 18449654196553852968254 |