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.

1, 2, 5, 10, 12, 25, 30, 50, 60, 62, 75, 125, 150, 155, 187, 250, 300, 310, 312, 360, 375, 387, 467, 625, 750, 775, 780, 900, 935, 937, 967, 1167, 1250, 1500, 1550, 1560, 1562, 1800, 1860, 1875, 1935, 1937, 1950, 2250, 2335, 2337, 2342, 2417, 2917

Offset: 1

Author

Clark Kimberling, Jul 04 2011

Keywords

• nonn

Crossrefs

Cf. A192476.

Programs

Mathematica

start = {1}; f[x_, y_] := 2 x*y + Floor[x*y/2]
b[x_] :=
  Block[{w = x},
   Select[Union[
     Flatten[AppendTo[w,
       Table[f[w[[i]], w[[j]]], {i, 1, Length[w]}, {j, 1, i}]]]], # <
      6000 &]];
t = FixedPoint[b, start] (* A192539 *)