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 | 7 |
| 2 | 99 |
| 3 | 700 |
| 4 | 9899 |
| 5 | 69993 |
| 6 | 989801 |
| 7 | 6998600 |
| 8 | 98970201 |
| 9 | 699790007 |
| 10 | 9896030299 |
| 11 | 69972002100 |
| 12 | 989504059699 |
| 13 | 6996500419993 |
| 14 | 98940509939601 |
| 15 | 699580069997200 |
| 16 | 9893061489900401 |
| 17 | 69951010499300007 |
| 18 | 989207208480100499 |
| 19 | 6994401469860003500 |
| 20 | 98910827786520149499 |