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.
{k>=0} of S is uniquely identified by the positive number f(X) = Product's wiki page.
{k>=0} of S is uniquely identified by the positive number f(X) = Product has authored 0 sequences.