A192646 First differences of A192645.

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, 5, 3, 369, 1, 135, 185, 192, 39, 8, 8, 5, 3, 1, 368, 190, 369, 1, 46, 89, 47, 8, 130, 192, 39, 16, 5, 3, 17, 118, 185, 49, 48, 87, 8, 39, 16, 5, 3, 114, 192, 39, 16, 5, 3, 48

Offset: 1

Author

Clark Kimberling, Jul 06 2011

Keywords

• nonn

Comments

Does this sequence include 1 infinitely many times?

Examples

			A192645 = (1, 2, 3, 5, 8, 16, 21, ...) gives (2-1, 3-2, 5-3, 8-5, 16-8, 21-16, ...)
		

Crossrefs

Cf. A192476, A192645.

Programs

Mathematica

start = {1, 2};
f[x_, y_] := If[MemberQ[Range[1, 5000], x^2 - y^2], x^2 - 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}]]]], # <
      5000 &]];
t = FixedPoint[b, start]  (* A192645 *)
Differences[t] (* A192646 *)