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 | -3 |
| 2 | -36 |
| 3 | -207 |
| 4 | -2214 |
| 5 | -2754 |
| 6 | -138591 |
| 7 | 547722 |
| 8 | -3730293 |
| 9 | 30138075 |
| 10 | 133709535 |
| 11 | 7735237479 |
| 12 | -35284817430 |
| 13 | 702841889322 |
| 14 | 3056530613769 |
| 15 | 9493893988155 |
| 16 | 112554319443867 |
| 17 | 3822223052352735 |
| 18 | -3940051663965051 |
| 19 | 250298859930263181 |
| 20 | -551418001934739786 |
| 21 | 1061747224529191191 |