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 | 3 |
| 2 | 12 |
| 3 | 552 |
| 4 | 6978816 |
| 5 | 429714433137180672 |
| 6 | 868161947968780041877535786874146453722578812928 |