A031811 - OEIS

%I #8 Nov 21 2013 12:46:30

%S 15871,30847,31171,41839,42631,54859,62923,65591,66187,68056,68944,

%T 69299,70855,77875,80999,83931,92491,95875,96695,97507,100264,106856,

%U 109336,109855,110707,115216,115519,122200,124415,124931,132995,135143,139551

%N Period of continued fraction for sqrt(n) contains exactly 43 ones.

%t cf43Q[n_]:=Module[{sn=Sqrt[n]},!IntegerQ[sn]&&Count[ ContinuedFraction[ sn][[2]],1]==43]; Select[Range[140000],cf43Q] (* _Harvey P. Dale_, Apr 25 2012 *)

%K nonn

%O 1,1

%A _David W. Wilson_