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) |
|---|---|
| 0 | 0 |
| 1 | 15 |
| 2 | 1155 |
| 3 | 111555 |
| 4 | 11115555 |
| 5 | 1111155555 |
| 6 | 111111555555 |
| 7 | 11111115555555 |
| 8 | 1111111155555555 |
| 9 | 111111111555555555 |
| 10 | 11111111115555555555 |
| 11 | 1111111111155555555555 |
| 12 | 111111111111555555555555 |