%I #12 Jul 11 2021 07:25:04
%S 271,382,581,607,681,753,789,826,871,911,1017,1072,1103,1147,1233,
%T 1255,1262,1349,1359,1438,1614,1674,1711,1795,1836,1838,1868,1888,
%U 1908,1922,1982,2048,2051,2063,2078,2107,2119,2143,2154,2254,2364,2367,2414,2439
%N Numbers k such that the continued fraction for sqrt(k) has period 24.
%t cf24Q[n_]:=Module[{s=Sqrt[n],c},c=If[IntegerQ[s],{1,1},ContinuedFraction[ s]][[2]];Length[c]==24]; Select[Range[2500],cf24Q] (* _Harvey P. Dale_, Mar 20 2021 *)
%K nonn
%O 1,1
%A _David W. Wilson_