login

Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.

Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 36.
0

%I #14 Jul 06 2024 16:00:55

%S 1298,1318,1346,1358,1362,1366,1382,1394,1398,1438,1442,2919,2949,

%T 2964,2973,2991,3057,3063,3081,3093,3102,3117,3153,3171,3174,3189,

%U 3207,3237,3246,5188,5204,5212,5228,5244,5252,5260,5276,5284,5300,5308,5324,5340

%N Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 36.

%t cf36Q[n_]:=Module[{s=Sqrt[n],cf,len},cf=If[IntegerQ[s],{1}, ContinuedFraction[ s][[2]]];len=Length[cf];EvenQ[len]&&cf[[len/2]] == 36]; Select[ Range[6000],cf36Q] (* _Harvey P. Dale_, Aug 23 2019 *)

%K nonn

%O 1,1

%A _David W. Wilson_