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 | -4 |
| 3 | 4 |
| 4 | 51 |
| 5 | -6 |
| 6 | -770 |
| 7 | -694 |
| 8 | 12363 |
| 9 | 25583 |
| 10 | -198824 |
| 11 | -701944 |
| 12 | 3049603 |
| 13 | 17238467 |
| 14 | -41348631 |
| 15 | -396817391 |
| 16 | 391720363 |
| 17 | 8689985437 |
| 18 | 1902247845 |
| 19 | -181526287908 |
| 20 | -253530149234 |
| 21 | 3597968506523 |
| 22 | 9727546141524 |
| 23 | -66671292054788 |
| 24 | -291760189535999 |
| 25 | 1116731578365699 |