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 | 9 |
| 2 | 99 |
| 3 | 909 |
| 4 | 919 |
| 5 | 929 |
| 6 | 939 |
| 7 | 949 |
| 8 | 959 |
| 9 | 969 |
| 10 | 979 |
| 11 | 989 |
| 12 | 999 |
| 13 | 9009 |
| 14 | 9119 |
| 15 | 9229 |
| 16 | 9339 |
| 17 | 9449 |
| 18 | 9559 |
| 19 | 9669 |
| 20 | 9779 |
| 21 | 9889 |
| 22 | 9999 |
| 23 | 90009 |
| 24 | 90109 |
| 25 | 90209 |
| 26 | 90309 |
| 27 | 90409 |
| 28 | 90509 |
| 29 | 90609 |
| 30 | 90709 |
| 31 | 90809 |
| 32 | 90909 |
| 33 | 91019 |
| 34 | 91119 |
| 35 | 91219 |
| 36 | 91319 |
| 37 | 91419 |
| 38 | 91519 |
| 39 | 91619 |
| 40 | 91719 |
| 41 | 91819 |
| 42 | 91919 |