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 | -21 |
| 3 | -7 |
| 4 | 739 |
| 5 | 1629 |
| 6 | -26859 |
| 7 | -118329 |
| 8 | 922419 |
| 9 | 6886397 |
| 10 | -27414191 |
| 11 | -358533429 |
| 12 | 539620621 |
| 13 | 17229485987 |
| 14 | 8782716411 |
| 15 | -769962297447 |
| 16 | -1897237412973 |
| 17 | 31786556599917 |
| 18 | 149610560086113 |
| 19 | -1182765435388341 |
| 20 | -9268347520205991 |
| 21 | 37049669347266471 |
| 22 | 505738623506722431 |