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 | 5 |
| 3 | -5 |
| 4 | -135 |
| 5 | -110 |
| 6 | 3661 |
| 7 | 16440 |
| 8 | -1375 |
| 9 | -827075 |
| 10 | -8388505 |
| 11 | 2298072 |
| 12 | 496514205 |
| 13 | 2782147265 |
| 14 | 322830120 |
| 15 | -164675585390 |
| 16 | -1846591014842 |
| 17 | -3084367863270 |
| 18 | 84920580735040 |
| 19 | 845318162940805 |
| 20 | 4163798547024100 |
| 21 | -18708392155753220 |
| 22 | -503209620889452990 |
| 23 | -3212928238924865090 |