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 | -23 |
| 3 | 6 |
| 4 | 1919 |
| 5 | -170 |
| 6 | -14729 |
| 7 | 9194 |
| 8 | 5159039 |
| 9 | -829746 |
| 10 | -1270389115 |
| 11 | 113574802 |
| 12 | 1230513089867 |
| 13 | -22005182602 |
| 14 | -4276962719801 |
| 15 | 5736562638330 |
| 16 | 108296822232645343 |
| 17 | -1936755687728738 |
| 18 | -9194150224979606003 |
| 19 | 822132393822871778 |
| 20 | 12552825267118398962989 |