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 | 0 |
| 2 | -1 |
| 3 | 2 |
| 4 | 0 |
| 5 | -2 |
| 6 | 3 |
| 7 | 8 |
| 8 | -259 |
| 9 | -9006 |
| 10 | 37575 |
| 11 | 1988916 |
| 12 | 41615129 |
| 13 | -444915500 |
| 14 | 4752358604 |
| 15 | -50506657344 |
| 16 | 532544416084 |
| 17 | -4450492081868 |
| 18 | -10234691885873 |
| 19 | 241215169689690 |
| 20 | 21696729746925312 |
| 21 | 123619114295636184 |
| 22 | 174381272189413488 |
| 23 | -43909101832286346168 |
| 24 | -439142701170244441024 |