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) |
|---|---|
| 1 | 0 |
| 2 | 12 |
| 3 | -24 |
| 4 | 168 |
| 5 | 1440 |
| 6 | 24480 |
| 7 | -297024 |
| 8 | 28017216 |
| 9 | -533681664 |
| 10 | 41156316672 |
| 11 | -503287538688 |
| 12 | 53001415916544 |
| 13 | -1839416689004544 |
| 14 | 246102905022713856 |
| 15 | -9001661201883684864 |