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 | 3 |
| 3 | 49 |
| 4 | 1401 |
| 5 | 106803 |
| 6 | 19457754 |
| 7 | 7600681910 |
| 8 | 7516309079483 |
| 9 | 16637614325062889 |