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.
%I A192539 #4 Mar 30 2012 18:57:35 %S A192539 1,2,5,10,12,25,30,50,60,62,75,125,150,155,187,250,300,310,312,360, %T A192539 375,387,467,625,750,775,780,900,935,937,967,1167,1250,1500,1550,1560, %U A192539 1562,1800,1860,1875,1935,1937,1950,2250,2335,2337,2342,2417,2917 %N A192539 Monotonic ordering of set S generated by these rules: if x and y are in S then 2xy+floor(xy/2) is in S, and 1 is in S. %t A192539 start = {1}; f[x_, y_] := 2 x*y + Floor[x*y/2] %t A192539 b[x_] := %t A192539 Block[{w = x}, %t A192539 Select[Union[ %t A192539 Flatten[AppendTo[w, %t A192539 Table[f[w[[i]], w[[j]]], {i, 1, Length[w]}, {j, 1, i}]]]], # < %t A192539 6000 &]]; %t A192539 t = FixedPoint[b, start] (* A192539 *) %Y A192539 Cf. A192476. %K A192539 nonn %O A192539 1,2 %A A192539 _Clark Kimberling_, Jul 04 2011