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.
?(Differences[#] == {6,6}&),{1},Heads->False]] (* _Harvey P. Dale's wiki page.
?(Differences[#] == {6,6}&),{1},Heads->False]] (* _Harvey P. Dale has authored 0 sequences.