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A192520 Monotonic ordering of set S generated by these rules: if x and y are in S then floor(x*y/2) is in S, and 5 is in S.

%I A192520 #5 Mar 30 2012 18:57:34
%S A192520 5,12,30,72,75,180,187,432,450,467,1080,1122,1125,1167,2592,2700,2802,
%T A192520 2805,2812,2917,6480,6732,6750,7002,7005,7012,7030,7292,15552,16200,
%U A192520 16812,16830,16872,16875,17484,17502,17505,17512,17530,17575,18230
%N A192520 Monotonic ordering of set S generated by these rules:  if x and y are in S then floor(x*y/2) is in S, and 5 is in S.
%t A192520 start = {5}; f[x_, y_] := Floor[x*y/2]
%t A192520 b[x_] :=
%t A192520   Block[{w = x},
%t A192520    Select[Union[
%t A192520      Flatten[AppendTo[w,
%t A192520        Table[f[w[[i]], w[[j]]], {i, 1, Length[w]}, {j, 1, i}]]]], # <
%t A192520       70000 &]];
%t A192520 t = NestList[b, start, 14][[-1]] (* A192520 *)
%t A192520 Table[t[[i]] - t[[i - 1]], {i, 2, Length[t]}]  (* difference sequence *)
%Y A192520 Cf. A192476.
%K A192520 nonn
%O A192520 1,1
%A A192520 _Clark Kimberling_, Jul 03 2011