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 | 5 |
| 2 | 11 |
| 3 | 151 |
| 4 | 1151 |
| 5 | 1511 |
| 6 | 11551 |
| 7 | 15511 |
| 8 | 15551 |
| 9 | 51151 |
| 10 | 51511 |
| 11 | 51551 |
| 12 | 55511 |
| 13 | 115151 |
| 14 | 511111 |
| 15 | 511151 |
| 16 | 515111 |
| 17 | 1111151 |
| 18 | 1115551 |
| 19 | 1155151 |
| 20 | 1551551 |
| 21 | 1555111 |
| 22 | 5115511 |
| 23 | 5151151 |
| 24 | 5151551 |
| 25 | 5155511 |
| 26 | 5511151 |
| 27 | 5511511 |
| 28 | 5515151 |
| 29 | 5551111 |
| 30 | 15511151 |