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 | 0 |
| 3 | 8 |
| 4 | -6 |
| 5 | 0 |
| 6 | 90 |
| 7 | -144 |
| 8 | 192 |
| 9 | 480 |
| 10 | -1372 |
| 11 | 2676 |
| 12 | 1703 |
| 13 | -11952 |
| 14 | 33316 |
| 15 | -18900 |
| 16 | -64201 |
| 17 | 304580 |
| 18 | -401068 |
| 19 | -97928 |
| 20 | 2390637 |
| 21 | -5130048 |
| 22 | 4264858 |
| 23 | 13518716 |
| 24 | -49117798 |
| 25 | 76725752 |
| 26 | 29308994 |
| 27 | -381566684 |
| 28 | 915306452 |