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 | 13 |
| 2 | 31 |
| 3 | 113 |
| 4 | 311 |
| 5 | 113131 |
| 6 | 131311 |
| 7 | 1131131 |
| 8 | 1133131 |
| 9 | 1133333 |
| 10 | 1311311 |
| 11 | 1313311 |
| 12 | 1331333 |
| 13 | 1333313 |
| 14 | 3111313 |
| 15 | 3131113 |
| 16 | 3133331 |
| 17 | 3331331 |
| 18 | 3333311 |
| 19 | 11113111 |
| 20 | 11131111 |
| 21 | 11311133 |
| 22 | 11313311 |
| 23 | 11331311 |
| 24 | 11333131 |
| 25 | 13131133 |
| 26 | 13133311 |
| 27 | 31111313 |
| 28 | 31311113 |
| 29 | 33111311 |
| 30 | 33113131 |