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 | 0 |
| 3 | -2 |
| 4 | 0 |
| 5 | 4 |
| 6 | 12 |
| 7 | -8 |
| 8 | -48 |
| 9 | -56 |
| 10 | -144 |
| 11 | 400 |
| 12 | 1200 |
| 13 | 1792 |
| 14 | 960 |
| 15 | 16864 |
| 16 | -34560 |
| 17 | -170816 |
| 18 | -320064 |
| 19 | -632960 |
| 20 | -869376 |
| 21 | -15780224 |
| 22 | 30636288 |
| 23 | 144493312 |
| 24 | 360770304 |
| 25 | 738095104 |
| 26 | 2382729216 |
| 27 | 6661606912 |
| 28 | 81815537664 |
| 29 | -152267942912 |
| 30 | -883849860096 |
| 31 | -2187970242560 |
| 32 | -6499788165120 |