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 | 4 |
| 2 | 28 |
| 3 | 1552 |
| 4 | 4817152 |
| 5 | 46409906716672 |
| 6 | 4307758882900393634270543872 |
| 7 | 37113573186414494550922197215584520229965687291643953152 |