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 | -39 |
| 3 | 55 |
| 4 | 39697 |
| 5 | -2289 |
| 6 | -235548247 |
| 7 | -1367615353 |
| 8 | 4617417380769 |
| 9 | 85802560805023 |
| 10 | -226896487004217095 |
| 11 | -9332987296855749801 |
| 12 | 23509703520941274769841 |
| 13 | 1792438008018628579394735 |