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 | 1 |
| 2 | -4 |
| 3 | 4 |
| 4 | -18 |
| 5 | -18 |
| 6 | 9 |
| 7 | -48 |
| 8 | -48 |
| 9 | -48 |
| 10 | 16 |
| 11 | -100 |
| 12 | -100 |
| 13 | -100 |
| 14 | -100 |
| 15 | 25 |
| 16 | -180 |
| 17 | -180 |
| 18 | -180 |
| 19 | -180 |
| 20 | -180 |
| 21 | 36 |
| 22 | -294 |
| 23 | -294 |
| 24 | -294 |
| 25 | -294 |
| 26 | -294 |
| 27 | -294 |
| 28 | 49 |