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 | 1 |
| 1 | 11 |
| 2 | 919 |
| 3 | 90109 |
| 4 | 9001009 |
| 5 | 900010009 |
| 6 | 90000100009 |
| 7 | 9000001000009 |
| 8 | 900000010000009 |
| 9 | 90000000100000009 |
| 10 | 9000000001000000009 |
| 11 | 900000000010000000009 |
| 12 | 90000000000100000000009 |
| 13 | 9000000000001000000000009 |
| 14 | 900000000000010000000000009 |
| 15 | 90000000000000100000000000009 |
| 16 | 9000000000000001000000000000009 |