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 | -30 |
| 2 | 480 |
| 3 | -5440 |
| 4 | 48930 |
| 5 | -371136 |
| 6 | 2464320 |
| 7 | -14688000 |
| 8 | 80001120 |
| 9 | -403533790 |
| 10 | 1904433984 |
| 11 | -8477603520 |
| 12 | 35829727680 |
| 13 | -144548556480 |
| 14 | 559157308800 |
| 15 | -2081866609920 |
| 16 | 7484792950050 |
| 17 | -26057409056640 |
| 18 | 88057506412320 |