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 | -3 |
| 3 | 5 |
| 4 | 25 |
| 5 | -343 |
| 6 | 2133 |
| 7 | -3603 |
| 8 | -112975 |
| 9 | 1938897 |
| 10 | -18008275 |
| 11 | 55198805 |
| 12 | 1753746377 |
| 13 | -45801271943 |
| 14 | 649021707397 |
| 15 | -4682002329795 |
| 16 | -50792700319903 |
| 17 | 2692784088681889 |
| 18 | -59182401177647011 |
| 19 | 801759226622986917 |
| 20 | -2169423359710146183 |
| 21 | -263145142263538606519 |
| 22 | 9869607872225170545333 |