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 | 1 |
| 2 | -257 |
| 3 | 6562 |
| 4 | -65281 |
| 5 | 390626 |
| 6 | -1686434 |
| 7 | 5764802 |
| 8 | -16711425 |
| 9 | 43053283 |
| 10 | -100390882 |
| 11 | 214358882 |
| 12 | -428373922 |
| 13 | 815730722 |
| 14 | -1481554114 |
| 15 | 2563287812 |
| 16 | -4278124289 |
| 17 | 6975757442 |
| 18 | -11064693731 |
| 19 | 16983563042 |
| 20 | -25500455906 |
| 21 | 37828630724 |
| 22 | -55090232674 |