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.
?(MemberQ[#, 3] &)], {n, 60}] (* _Harvey P. Dale's wiki page.
?(MemberQ[#, 3] &)], {n, 60}] (* _Harvey P. Dale has authored 0 sequences.