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 | 13 |
| 3 | 181 |
| 4 | 2521 |
| 5 | 489061 |
| 6 | 6811741 |
| 7 | 1321442641 |
| 8 | 18405321661 |
| 9 | 381765135195632792959100810331957408101589361 |