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 | 2 |
| 2 | 5 |
| 3 | 193 |
| 4 | 613 |
| 5 | 1124581 |
| 6 | 52071301 |
| 7 | 213536830501 |