login
A192650
First differences of A192649.
2
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, 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, 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
OFFSET
1,5
COMMENTS
Are there infinitely many pairs 1,1?
MATHEMATICA
start = {1, 2, 4};
f[x_, y_] := If[MemberQ[Range[1, 700], 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}]]]], # <
700 &]];
t = FixedPoint[b, start] (* A192649 *)
Differences[t] (* A192650 *)
CROSSREFS
Sequence in context: A335174 A082905 A141524 * A178059 A116188 A318274
KEYWORD
nonn
AUTHOR
Clark Kimberling, Jul 06 2011
STATUS
approved