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 | 19 |
| 2 | 11919199 |
| 3 | 11919991 |
| 4 | 19111999 |
| 5 | 19199119 |
| 6 | 19911919 |
| 7 | 19991911 |
| 8 | 91919911 |
| 9 | 91999111 |
| 10 | 99111919 |
| 11 | 99119191 |
| 12 | 99919111 |
| 13 | 1111919999 |
| 14 | 1111999199 |
| 15 | 1191911999 |
| 16 | 1191919991 |
| 17 | 1191991991 |
| 18 | 1191999119 |
| 19 | 1199911919 |
| 20 | 1199911991 |
| 21 | 1199919191 |
| 22 | 1199919911 |
| 23 | 1911919199 |
| 24 | 1911991919 |