A192648 - OEIS

A192648

Monotonic ordering of set S generated by these rules: if x and y are in S and x^2-y^2>0 then x^2-y^2 is in S, and 2 and 3 are in S.

%I #8 Sep 15 2018 08:52:41

%S 2,3,5,16,21,185,231,247,252,416,432,437,2495,4345,7648,10143,13568,

%T 17913,19136,26784,29279,33784,33969,34200,34216,34221,52920,53105,

%U 53336,53352,53357,60568,60753,60984,61000,61005,63063,63248,63479

%N Monotonic ordering of set S generated by these rules: if x and y are in S and x^2-y^2>0 then x^2-y^2 is in S, and 2 and 3 are in S.

%C See A192645.

%H Ivan Neretin, <a href="/A192648/b192648.txt">Table of n, a(n) for n = 1..10000</a>

%t start = {2, 3};

%t f[x_, y_] := If[MemberQ[Range[1, 150000], x^2 - y^2], x^2 - y^2]

%t b[x_] :=

%t Block[{w = x},

%t Select[Union[

%t Flatten[AppendTo[w,

%t Table[f[w[[i]], w[[j]]], {i, 1, Length[w]}, {j, 1, i}]]]], # <

%t 150000 &]];

%t t = FixedPoint[b, start] (* A192648 *)

%Y Cf. A192476, A192646.

%K nonn

%O 1,1

%A _Clark Kimberling_, Jul 06 2011