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 | 9 |
| 2 | 81 |
| 3 | 18081 |
| 4 | 264639729 |
| 5 | 239657412990669 |
| 6 | 14022194613733384575957 |
| 7 | 55099298574634623527360069025765 |