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.
?(#2 < 2 #1 & @@ # &)] == 0, #, Block[{k = 1}, While[! IntegerQ@ HarmonicMean@{k, #}, k++]; k]] &, 76] (* _Michael De Vlieger has authored 0 sequences.