A024764 Every prefix prime in base 4 (written in base 4).
2, 3, 23, 31, 233, 311, 2333
Offset: 1
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.