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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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

COMMENTS

Are there infinitely many pairs 1,1?

LINKS

Table of n, a(n) for n=1..97.

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

Cf. A192649, A192646.

Sequence in context: A110570 A082905 A141524 * A178059 A116188 A318274

Adjacent sequences:  A192647 A192648 A192649 * A192651 A192652 A192653

KEYWORD

nonn

AUTHOR

Clark Kimberling, Jul 06 2011

STATUS

approved

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Last modified February 21 19:30 EST 2019. Contains 320376 sequences. (Running on oeis4.)