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 | 0 |
| 2 | -2 |
| 3 | -6 |
| 4 | -29 |
| 5 | -196 |
| 6 | -1665 |
| 7 | -16796 |
| 8 | -194905 |
| 9 | -2549468 |
| 10 | -37055681 |
| 11 | -592013436 |
| 12 | -10307671769 |
| 13 | -194225544124 |
| 14 | -3937581243201 |
| 15 | -85460277981116 |
| 16 | -1977127315636969 |
| 17 | -48573021658496348 |
| 18 | -1262954975286604673 |
| 19 | -34650561545808167292 |
| 20 | -1000438355724912080873 |