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 | -1 |
| 3 | 6 |
| 4 | 1 |
| 5 | -48 |
| 6 | 147 |
| 7 | -5 |
| 8 | 1584 |
| 9 | -24255 |
| 10 | 50176 |
| 11 | 1 |
| 12 | -1980 |
| 13 | 121275 |
| 14 | -1003520 |
| 15 | 1571724 |
| 16 | -41 |
| 17 | 496980 |
| 18 | -113458275 |
| 19 | 2950635520 |
| 20 | -16174611684 |
| 21 | 20412000000 |
| 22 | 45182 |
| 23 | -3322062810 |
| 24 | 2744728561050 |
| 25 | -206756932157440 |
| 26 | 3081396966348393 |
| 27 | -12443694076800000 |
| 28 | 13160600037440625 |
| 29 | -1294492177294 |