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A020364
Numbers k such that the continued fraction for sqrt(k) has period 25.
0
457, 881, 1049, 1181, 1189, 1306, 1585, 1594, 1754, 2125, 2797, 2906, 4121, 4157, 4234, 4253, 4330, 4442, 4469, 4517, 4913, 5077, 5597, 6418, 7442, 8249, 8345, 8570, 8689, 8825, 9593, 10145, 10301, 10498, 10625, 10673, 10889, 11401, 11930, 12053
OFFSET
1,1
MATHEMATICA
cf25Q[n_]:=Module[{s=Sqrt[n]}, If[IntegerQ[s], 1, Length[ ContinuedFraction[ s][[2]]]]==25]; Select[Range[13000], cf25Q] (* Harvey P. Dale, May 05 2020 *)
CROSSREFS
Sequence in context: A325086 A215895 A142828 * A337847 A093058 A201257
KEYWORD
nonn
STATUS
approved