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 | 1 |
| 2 | -2 |
| 3 | 5 |
| 4 | -68 |
| 5 | 193 |
| 6 | -655 |
| 7 | 19349 |
| 8 | -57736 |
| 9 | 520343 |
| 10 | -43184789 |
| 11 | 366043159 |
| 12 | -36085302154 |
| 13 | 219183008719 |
| 14 | -333043820161 |
| 15 | 1124780733391 |
| 16 | -2033896175720464 |
| 17 | 6178608669563333 |
| 18 | -106918567902798017 |
| 19 | 178383998798531120359 |
| 20 | -54061775649488096702 |
| 21 | 2291400664110090118501 |
| 22 | -56920102349900658177643 |