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 | 1 |
| 2 | 73 |
| 3 | 793 |
| 4 | 7993 |
| 5 | 79993 |
| 6 | 799993 |
| 7 | 7999993 |
| 8 | 79999993 |
| 9 | 799999993 |
| 10 | 7999999993 |
| 11 | 79999999993 |
| 12 | 799999999993 |
| 13 | 7999999999993 |
| 14 | 79999999999993 |
| 15 | 799999999999993 |
| 16 | 7999999999999993 |
| 17 | 79999999999999993 |
| 18 | 799999999999999993 |
| 19 | 7999999999999999993 |
| 20 | 79999999999999999993 |
| 21 | 799999999999999999993 |