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 | 0 |
| 2 | 2 |
| 3 | -13 |
| 4 | 127 |
| 5 | -1573 |
| 6 | 23711 |
| 7 | -421356 |
| 8 | 8626668 |
| 9 | -199971255 |
| 10 | 5177291275 |
| 11 | -148078588667 |
| 12 | 4636966634653 |
| 13 | -157786054331852 |
| 14 | 5797411243015250 |
| 15 | -228749440644895405 |
| 16 | 9646951350227609155 |
| 17 | -433035586385769361001 |
| 18 | 20614401475233006857035 |
| 19 | -1037331650810058231498688 |