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 | 3 |
| 3 | 7 |
| 4 | 9 |
| 5 | 37 |
| 6 | 49 |
| 7 | 99 |
| 8 | 379 |
| 9 | 399 |
| 10 | 787 |
| 11 | 799 |
| 12 | 1989 |
| 13 | 1999 |
| 14 | 3999 |
| 15 | 6997 |
| 16 | 17899 |
| 17 | 18999 |
| 18 | 38989 |
| 19 | 67999 |
| 20 | 79899 |
| 21 | 79999 |
| 22 | 389899 |
| 23 | 499989 |
| 24 | 798979 |
| 25 | 897999 |
| 26 | 989899 |
| 27 | 2999997 |
| 28 | 2899999 |
| 29 | 4998999 |