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 | 1 |
| 2 | 31 |
| 3 | 313 |
| 4 | 1313 |
| 5 | 13131 |
| 6 | 313131 |
| 7 | 3131313 |
| 8 | 13131313 |
| 9 | 131313131 |
| 10 | 3131313131 |
| 11 | 31313131313 |
| 12 | 131313131313 |
| 13 | 1313131313131 |
| 14 | 31313131313131 |
| 15 | 313131313131313 |
| 16 | 1313131313131313 |
| 17 | 13131313131313131 |
| 18 | 313131313131313131 |