

A031566


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 68.


0



4626, 4642, 4678, 4694, 4702, 4722, 4726, 4742, 4766, 4786, 4798, 4802, 4806, 4818, 4822, 4834, 4838, 4846, 4854, 4866, 4882, 4894, 4898, 10407, 10446, 10452, 10473, 10479, 10497, 10524, 10533, 10551, 10569, 10581, 10587, 10596, 10617, 10623, 10641
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OFFSET

1,1


LINKS



MATHEMATICA

cf68Q[n_]:=Module[{s=Sqrt[n], cf, len}, cf=If[IntegerQ[s], {1}, ContinuedFraction[ s][[2]]]; len=Length[cf]; EvenQ[len]&&cf[[len/2]]==68]; Select[Range[11000], cf68Q] (* Harvey P. Dale, Jan 10 2019 *)


CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



