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 | 0 |
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 0 |
| 5 | 28 |
| 6 | -85 |
| 7 | 1029 |
| 8 | -6440 |
| 9 | 79136 |
| 10 | -724305 |
| 11 | 9982005 |
| 12 | -118974856 |
| 13 | 1858582100 |
| 14 | -27126378357 |
| 15 | 478338929509 |
| 16 | -8227405849840 |
| 17 | 162502213354272 |
| 18 | -3209170996757057 |
| 19 | 70409595412300877 |
| 20 | -1566861832498793248 |
| 21 | 37885426233247176772 |
| 22 | -936732798302547171509 |
| 23 | 24780850678372964078189 |