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 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | -2 |
| 6 | -3 |
| 7 | -3 |
| 8 | 1 |
| 9 | -72 |
| 10 | 3303 |
| 11 | 10788 |
| 12 | 287767 |
| 13 | -2441508 |
| 14 | 41165366097 |
| 15 | 1073195273432754 |
| 16 | 155912367904160034530 |
| 17 | 3136560083478359027185613587 |
| 18 | 539970867097445764756784886568605205005 |
| 19 | -6513790584274345956893756600832505179138091590508595552 |