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A192646 First differences of A192645.

%I A192646 #9 Jun 26 2017 01:06:25
%S A192646 1,1,2,3,8,5,3,15,16,5,3,72,50,7,39,16,5,3,65,49,8,39,16,5,3,72,39,16,
%T A192646 5,3,369,1,135,185,192,39,8,8,5,3,1,368,190,369,1,46,89,47,8,130,192,
%U A192646 39,16,5,3,17,118,185,49,48,87,8,39,16,5,3,114,192,39,16,5,3,48
%N A192646 First differences of A192645.
%C A192646 Does this sequence include 1 infinitely many times?
%e A192646 A192645 = (1, 2, 3, 5, 8, 16, 21, ...) gives (2-1, 3-2, 5-3, 8-5, 16-8, 21-16, ...)
%t A192646 start = {1, 2};
%t A192646 f[x_, y_] := If[MemberQ[Range[1, 5000], x^2 - y^2], x^2 - y^2]
%t A192646 b[x_] :=
%t A192646   Block[{w = x},
%t A192646    Select[Union[
%t A192646      Flatten[AppendTo[w,
%t A192646        Table[f[w[[i]], w[[j]]], {i, 1, Length[w]}, {j, 1, i}]]]], # <
%t A192646       5000 &]];
%t A192646 t = FixedPoint[b, start]  (* A192645 *)
%t A192646 Differences[t] (* A192646 *)
%Y A192646 Cf. A192476, A192645.
%K A192646 nonn
%O A192646 1,3
%A A192646 _Clark Kimberling_, Jul 06 2011