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 | 27 |
| 2 | 1092727 |
| 3 | 1000030900318271092727 |
| 4 | 1000000000000003000030900000003000061800318271000030900318271092727 |