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) |
|---|---|
| 1 | 0 |
| 2 | 255 |
| 3 | 72057594037927935 |
| 4 | 452312848583266388373324160190187140051835877600158453279131187530910662655 |