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A020407
Numbers k such that the continued fraction for sqrt(k) has period 68.
0
1879, 1951, 2239, 3079, 3244, 3991, 4231, 4567, 4689, 4871, 5361, 5553, 5937, 5998, 6044, 6064, 6295, 6304, 6346, 6535, 6719, 6906, 7276, 7564, 7615, 7629, 8423, 8444, 8748, 8764, 8894, 8896, 8959, 9007, 9117, 9223, 9276, 9358, 9564, 9741, 9784, 10078
OFFSET
1,1
MATHEMATICA
cf68Q[n_]:=Module[{s=Sqrt[n]}, If[IntegerQ[s], 1, Length[ ContinuedFraction[ s][[2]]]]==68]; Select[Range[11000], cf68Q] (* Harvey P. Dale, Aug 20 2015 *)
CROSSREFS
Cf. A003285.
Sequence in context: A127410 A237570 A045201 * A320719 A358147 A235193
KEYWORD
nonn
STATUS
approved