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 | -3 |
| 3 | 8 |
| 4 | -21 |
| 5 | 45 |
| 6 | -81 |
| 7 | -504 |
| 8 | -327 |
| 9 | -95 |
| 10 | -27 |
| 11 | 3744 |
| 12 | -514125 |
| 13 | 42577129 |
| 14 | -594343521 |
| 15 | 6384803528 |
| 16 | 55828902985 |
| 17 | 222653960625 |
| 18 | -24898185972135 |
| 19 | 370012327363008 |
| 20 | -5108693773098321 |
| 21 | 66203904684406485 |
| 22 | -696661740301346521 |
| 23 | 5010137735370840432 |
| 24 | -22341106332701627463 |