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A031612 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 24. 0

%I #12 Aug 18 2021 00:10:32

%S 145,7274,11962,18077,18617,26413,32986,33349,34081,35194,42314,44389,

%T 45233,54185,55117,65977,68041,69085,77258,77813,78929,81754,91226,

%U 91829,94261,94874,95489,123341,140837,141586,143090,145361,146122,147650

%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 24.

%t cf24Q[n_]:=Module[{s=Sqrt[n],cf,len},cf=If[IntegerQ[s],{1,1}, ContinuedFraction[ s][[2]]];len=Length[cf];OddQ[len] && cf[[(len+1)/2]] == 24]; Select[Range[150000],cf24Q] (* _Harvey P. Dale_, Mar 17 2016 *)

%K nonn

%O 1,1

%A _David W. Wilson_

%E Terms and definition corrected by _Harvey P. Dale_, Mar 17 2016

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