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A031620 Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted the two central terms are both 32. 0

%I #16 May 01 2022 17:50:35

%S 13274,21106,21397,21985,44269,58789,75914,77573,78689,93997,96461,

%T 114685,116041,118777,120157,139658,143413,162229,163034,163841,

%U 167906,169546,170369,196093,219865,227417,229325,249962,250961,252965,253970

%N Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted the two central terms are both 32.

%t cf32Q[n_]:=Module[{s=Sqrt[n],cf,len},cf=If[IntegerQ[s],{1,1},ContinuedFraction[ s][[2]]];len=Length[cf];OddQ[len]&&cf[[Floor[len/2]]]==cf[[Ceiling[len/2]]] == 32]; Select[ Range[254000],cf32Q] (* _Harvey P. Dale_, May 01 2022 *)

%Y Subsequence of A003814.

%K nonn

%O 1,1

%A _David W. Wilson_

%E First term 1025 removed by _Georg Fischer_, Jun 16 2019

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Last modified April 25 11:39 EDT 2024. Contains 371969 sequences. (Running on oeis4.)