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 | 12 |
| 4 | -118 |
| 5 | 1605 |
| 6 | -27816 |
| 7 | 585046 |
| 8 | -14459138 |
| 9 | 410368743 |
| 10 | -13146830110 |
| 11 | 469123986529 |
| 12 | -18447791712945 |
| 13 | 792514583941223 |
| 14 | -36925394368325295 |
| 15 | 1854525584914459755 |
| 16 | -99872579714406393286 |
| 17 | 5740977285851988017769 |
| 18 | -350847888975706702249890 |