%I
%S 61,97,233,298,317,554,757,773,794,797,1322,1385,1429,1625,1658,1730,
%T 1769,1865,1973,2069,2081,2218,2249,2285,2357,2465,2690,2890,2941,
%U 2986,3233,3242,3341,3538,3545,3986,4250,4274,4553,4597,4610,4649,4682,4889
%N Numbers k such that the continued fraction for sqrt(k) has period 11.
%t cf11Q[n_]:=Module[{s=Sqrt[n]},If[IntegerQ[s],1,Length[ ContinuedFraction[ s][[2]]]]==11]; Select[Range[5000],cf11Q] (* _Harvey P. Dale_, Mar 28 2019 *)
%K nonn
%O 1,1
%A _David W. Wilson_
