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 | 3 |
| 2 | 72 |
| 3 | 439128 |
| 4 | 84722519069640072 |
| 5 | 608130213374088941214747405817720857404971722895128 |