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 | -23 |
| 2 | 230 |
| 3 | -1311 |
| 4 | 4853 |
| 5 | -14191 |
| 6 | 44873 |
| 7 | -154859 |
| 8 | 454043 |
| 9 | -1139765 |
| 10 | 3085358 |
| 11 | -8930785 |
| 12 | 22848752 |
| 13 | -53971892 |
| 14 | 137067350 |
| 15 | -351827803 |
| 16 | 829356379 |
| 17 | -1915368585 |
| 18 | 4586707633 |
| 19 | -10818772384 |
| 20 | 24533286122 |
| 21 | -55227022631 |