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 | 89 |
| 3 | 997 |
| 4 | 8999 |
| 5 | 99989 |
| 6 | 989999 |
| 7 | 9899999 |
| 8 | 99999989 |
| 9 | 998999999 |
| 10 | 9999898999 |
| 11 | 99989999999 |
| 12 | 999999999989 |
| 13 | 9999999999799 |
| 14 | 99999999899999 |
| 15 | 999999999999989 |
| 16 | 9999999999989999 |
| 17 | 99999999999899999 |
| 18 | 999999999999999989 |
| 19 | 9998999999999999999 |
| 20 | 99999999999999999989 |