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 | -8 |
| 3 | 15 |
| 4 | 0 |
| 5 | -94 |
| 6 | -512 |
| 7 | 987 |
| 8 | 0 |
| 9 | -7346 |
| 10 | 65536 |
| 11 | -122058 |
| 12 | 0 |
| 13 | -2757820 |
| 14 | -22020096 |
| 15 | 59250963 |
| 16 | 0 |
| 17 | -329425898 |
| 18 | 2617245696 |
| 19 | -4805611678 |
| 20 | -34359738368 |
| 21 | -19403249316 |
| 22 | 498216206336 |
| 23 | -36302282082 |
| 24 | 0 |
| 25 | 14136557849100 |
| 26 | -71399536328704 |
| 27 | -88183884706356 |