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 | 9 |
| 2 | 81 |
| 3 | 361 |
| 4 | 1521 |
| 5 | 6889 |
| 6 | 29929 |
| 7 | 127449 |
| 8 | 546121 |
| 9 | 2337841 |
| 10 | 9979281 |
| 11 | 42601729 |
| 12 | 181899169 |
| 13 | 776458225 |
| 14 | 3314189761 |
| 15 | 14146485721 |
| 16 | 60382741441 |
| 17 | 257733905625 |
| 18 | 1100096811025 |
| 19 | 4695589958761 |
| 20 | 20042356043161 |
| 21 | 85547497157721 |