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 | 189 |
| 4 | 441 |
| 5 | 2163 |
| 6 | 10609 |
| 7 | 33063 |
| 8 | 103041 |
| 9 | 418263 |
| 10 | 1697809 |
| 11 | 5875227 |
| 12 | 20331081 |
| 13 | 77333859 |
| 14 | 294156801 |
| 15 | 1057136187 |
| 16 | 3799119769 |
| 17 | 14123193995 |
| 18 | 52502848225 |
| 19 | 191262879795 |
| 20 | 696752470089 |
| 21 | 2569117858827 |
| 22 | 9473043664561 |
| 23 | 34677617171731 |