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 | 4 |
| 3 | 3511808 |
| 4 | 16417340254783504656 |
| 5 | 1461340738496783113671688672284985566897802138624 |
| 6 | 3940200619620187981589093886506105584397793947159777 |