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 | -3 |
| 3 | 14 |
| 4 | -81 |
| 5 | 528 |
| 6 | -3708 |
| 7 | 27388 |
| 8 | -209739 |
| 9 | 1650204 |
| 10 | -13258230 |
| 11 | 108311352 |
| 12 | -896946048 |
| 13 | 7512187398 |
| 14 | -63520243398 |
| 15 | 541511083648 |
| 16 | -4649182740159 |
| 17 | 40163784583752 |
| 18 | -348870785898510 |
| 19 | 3045109181792304 |
| 20 | -26694854975488554 |
| 21 | 234936349043049246 |
| 22 | -2074958037081265050 |