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 | -4 |
| 2 | -4 |
| 3 | -16 |
| 4 | -84 |
| 5 | -496 |
| 6 | -3120 |
| 7 | -20416 |
| 8 | -137300 |
| 9 | -942384 |
| 10 | -6572336 |
| 11 | -46432960 |
| 12 | -331580272 |
| 13 | -2389352256 |
| 14 | -17351364160 |
| 15 | -126851634432 |
| 16 | -932823545428 |
| 17 | -6895102385072 |
| 18 | -51199649648048 |
| 19 | -381738099675840 |
| 20 | -2856639909232112 |