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" if is_prime("1234567891" . "0"x$'s wiki page.
\n" if is_prime("1234567891" . "0"x$ has authored 0 sequences.