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.
?(#==MoebiusMu[ n+1]&)],{n,0,Length[mu]}]] (* _Harvey P. Dale's wiki page.
?(#==MoebiusMu[ n+1]&)],{n,0,Length[mu]}]] (* _Harvey P. Dale has authored 0 sequences.