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 | 7 |
| 2 | 727 |
| 3 | 72727 |
| 4 | 77377 |
| 5 | 1777771 |
| 6 | 7772777 |
| 7 | 17772727771 |
| 8 | 777767777 |
| 9 | 72777777727 |
| 10 | 77777677777 |
| 11 | 7767777777677 |
| 12 | 7777774777777 |
| 13 | 377777777777773 |
| 14 | 777777727777777 |
| 15 | 72777777777777727 |
| 16 | 77777777677777777 |
| 17 | 7776777777777776777 |
| 18 | 717777777787777777717 |
| 19 | 737777777777777777737 |