A031783 - OEIS

%I #7 May 09 2021 10:46:45

%S 871,2675,3683,4819,5863,6731,8056,8827,9592,9971,10207,10323,12019,

%T 12455,12584,15224,15563,15696,16168,16536,16808,17155,17235,18535,

%U 19039,20923,20995,21255,21576,22608,24464,24495,24883,26151,26207,26827,26967

%N Period of continued fraction for sqrt(n) contains exactly 15 ones.

%t cf15Q[n_]:=Module[{s=Sqrt[n]},If[IntegerQ[s],1,Count[ContinuedFraction[ s] [[2]],1]]==15]; Select[Range[27000],cf15Q] (* _Harvey P. Dale_, May 09 2021 *)

%K nonn

%O 1,1

%A _David W. Wilson_