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.
?(PrimeQ[#]&)]<Count[idn,'s wiki page.
?(PrimeQ[#]&)]<Count[idn, has authored 0 sequences.