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 | -1 |
| 3 | 8 |
| 4 | 15 |
| 5 | 124 |
| 6 | -3340 |
| 7 | -9311 |
| 8 | -102641 |
| 9 | -1880812 |
| 10 | 150047424 |
| 11 | 692058289 |
| 12 | 8916106452 |
| 13 | 167039809897 |
| 14 | 7435628931289 |
| 15 | -1381243302601067 |
| 16 | -9407162843960561 |
| 17 | -165954439670564988 |
| 18 | -3103870029424074136 |
| 19 | -123659189880256295879 |
| 20 | -10671656695397289496160 |