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 | -2 |
| 2 | 2 |
| 3 | 4 |
| 4 | -24 |
| 5 | 48 |
| 6 | 24 |
| 7 | -464 |
| 8 | 1376 |
| 9 | -704 |
| 10 | -9920 |
| 11 | 41600 |
| 12 | -55040 |
| 13 | -201216 |
| 14 | 1266048 |
| 15 | -2628864 |
| 16 | -3021312 |
| 17 | 37696512 |
| 18 | -108659712 |
| 19 | 15857664 |
| 20 | 1067003904 |
| 21 | -4155138048 |
| 22 | 4378226688 |
| 23 | 27416125440 |
| 24 | -149814263808 |
| 25 | 273526325248 |
| 26 | 569660309504 |
| 27 | -5103546466304 |
| 28 | 13241145229312 |
| 29 | 4914079858688 |