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A192650 First differences of A192649.

%I A192650 #6 Sep 26 2016 21:43:16
%S A192650 1,1,1,1,2,1,1,3,3,1,1,4,3,7,1,1,6,1,5,3,7,1,4,3,1,1,7,5,2,1,1,14,16,
%T A192650 1,7,8,1,1,6,5,3,1,1,7,7,2,14,1,9,7,8,7,1,1,7,5,2,1,1,6,9,7,5,3,1,1,7,
%U A192650 9,6,1,5,2,1,1,8,15,8,31,9,9,8,8,7,23,1,1,8,7,5,3,7,1,1,15,7,24,1
%N A192650 First differences of A192649.
%C A192650 Are there infinitely many pairs 1,1?
%t A192650 start = {1, 2, 4};
%t A192650 f[x_, y_] := If[MemberQ[Range[1, 700], x^2 - y^2], x^2 - y^2]
%t A192650 b[x_] :=
%t A192650   Block[{w = x},
%t A192650    Select[Union[
%t A192650      Flatten[AppendTo[w,
%t A192650        Table[f[w[[i]], w[[j]]], {i, 1, Length[w]}, {j, 1, i}]]]], # <
%t A192650       700 &]];
%t A192650 t = FixedPoint[b, start]  (* A192649 *)
%t A192650 Differences[t] (* A192650 *)
%Y A192650 Cf. A192649, A192646.
%K A192650 nonn
%O A192650 1,5
%A A192650 _Clark Kimberling_, Jul 06 2011