%I #13 Nov 21 2013 12:46:30
%S 5539,7099,11227,11651,12367,15007,15343,17763,18091,19027,24287,
%T 24779,24895,28408,28792,32248,35375,39183,39783,40255,40888,42355,
%U 44239,44951,45123,45171,45671,46096,46779,49864,50803,50944,51895,52235,52599,53215
%N Period of continued fraction for sqrt(n) contains exactly 27 ones.
%C Are there any prime numbers in this sequence? - Zak Seidov, Feb 18 2012
%H Zak Seidov, <a href="/A031795/b031795.txt">Table of n, a(n) for n = 1..1000</a>
%t cf27Q[n_]:=Module[{sqrtn=Sqrt[n]},!IntegerQ[sqrtn]&&Count[ ContinuedFraction[ sqrtn][[2]],1]==27]; Select[Range[55000],cf27Q] (* _Harvey P. Dale_, Feb 18 2012 *)
%K nonn
%O 1,1
%A _David W. Wilson_