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 | -7 |
| 3 | -643 |
| 4 | -13583 |
| 5 | -29957 |
| 6 | -24277937 |
| 7 | -6382646731 |
| 8 | 2027394133729 |
| 9 | 10948179003324221 |
| 10 | 177623182156029053 |
| 11 | 126604967848904128751 |
| 12 | -2640658729595838040517543 |
| 13 | -423778395125199663867841 |