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 | 0 |
| 1 | 21 |
| 2 | 483 |
| 3 | 7785 |
| 4 | 107787 |
| 5 | 1377789 |
| 6 | 16777791 |
| 7 | 197777793 |
| 8 | 2277777795 |
| 9 | 25777777797 |
| 10 | 287777777799 |
| 11 | 3177777777801 |
| 12 | 34777777777803 |
| 13 | 377777777777805 |
| 14 | 4077777777777807 |
| 15 | 43777777777777809 |
| 16 | 467777777777777811 |