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 | 193939 |
| 2 | 199933 |
| 3 | 319993 |
| 4 | 331999 |
| 5 | 391939 |
| 6 | 393919 |
| 7 | 919393 |
| 8 | 933199 |
| 9 | 939193 |
| 10 | 939391 |
| 11 | 993319 |
| 12 | 999331 |
| 13 | 1313999 |
| 14 | 1317727 |
| 15 | 1399913 |
| 16 | 1731893 |
| 17 | 1743737 |
| 18 | 1772713 |
| 19 | 1893173 |
| 20 | 1977779 |
| 21 | 2713177 |
| 22 | 3139991 |
| 23 | 3173189 |
| 24 | 3177271 |
| 25 | 3189317 |
| 26 | 3717437 |
| 27 | 4373717 |
| 28 | 7174373 |
| 29 | 7271317 |
| 30 | 7318931 |