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 | 0 |
| 4 | 6 |
| 5 | 32 |
| 6 | 115 |
| 7 | 172 |
| 8 | -2030 |
| 9 | -29013 |
| 10 | -250051 |
| 11 | -1587556 |
| 12 | -5178877 |
| 13 | 52922256 |
| 14 | 1435509569 |
| 15 | 20813187553 |
| 16 | 230664704969 |
| 17 | 1884809758791 |
| 18 | 5120430335582 |
| 19 | -216605840330716 |
| 20 | -6440821191934686 |
| 21 | -122368984222010397 |
| 22 | -1842986108839510180 |
| 23 | -21473141673616814694 |