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 | 9 |
| 3 | 81 |
| 4 | 99 |
| 5 | 891 |
| 6 | 9801 |
| 7 | 9801 |
| 8 | 19602 |
| 9 | 39204 |
| 10 | 79497 |
| 11 | 499851 |
| 12 | 548856 |
| 13 | 1077021 |
| 14 | 2274822 |
| 15 | 4459554 |
| 16 | 8909109 |
| 17 | 70282971 |
| 18 | 87111288 |
| 19 | 664223571 |
| 20 | 730645938 |
| 21 | 5791910751 |
| 22 | 6272012637 |
| 23 | 36351143631 |
| 24 | 49985258994 |
| 25 | 88971507999 |
| 26 | 789520249881 |
| 27 | 868572264879 |
| 28 | 7470454307481 |