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A031617 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 29. 0

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

%S 5501,10453,17770,18037,26365,27017,36269,49066,63793,76537,81017,

%T 112754,114773,116129,132394,133121,134581,135314,136049,136786,

%U 138266,139009,139754,140501,154393,159133,180617,185741,187465,203461,204362

%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 29.

%t opct29Q[n_]:=Module[{cf=ContinuedFraction[Sqrt[n]][[2]],len}, len= Length[ cf]; OddQ[len]&&cf[[Floor[len/2]]]==29]; Select[Range[205000], !IntegerQ[Sqrt[#]]&&opct29Q[#]&] (* _Harvey P. Dale_, Dec 14 2011 *)

%Y Subsequence of A003814.

%K nonn

%O 1,1

%A _David W. Wilson_

%E Corrected by _Harvey P. Dale_, Dec 14 2011

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Last modified April 15 00:51 EDT 2024. Contains 371667 sequences. (Running on oeis4.)