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 | 11 |
| 2 | 101 |
| 3 | 191 |
| 4 | 919 |
| 5 | 11411 |
| 6 | 19991 |
| 7 | 91019 |
| 8 | 94049 |
| 9 | 94949 |
| 10 | 1114111 |
| 11 | 1190911 |
| 12 | 1409041 |
| 13 | 1411141 |
| 14 | 1444441 |
| 15 | 1490941 |
| 16 | 1909091 |
| 17 | 1941491 |
| 18 | 9049409 |
| 19 | 9091909 |
| 20 | 9109019 |
| 21 | 9110119 |
| 22 | 9149419 |
| 23 | 9199919 |
| 24 | 9400049 |
| 25 | 9414149 |
| 26 | 9419149 |
| 27 | 9440449 |
| 28 | 9919199 |