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A020417
Numbers k such that the continued fraction for sqrt(k) has period 78.
0
1894, 2539, 3241, 3862, 4417, 4691, 4989, 5158, 5251, 5366, 5489, 5977, 6139, 6393, 6514, 6628, 7081, 7286, 7414, 7576, 7941, 8699, 8913, 9019, 9186, 9329, 9491, 9547, 9764, 10105, 10157, 10351, 10436, 10456, 10821, 10916, 11012, 11153, 11469, 11586
OFFSET
1,1
MATHEMATICA
cf78Q[n_]:=Module[{s=Sqrt[n]}, If[IntegerQ[s], 1, Length[ ContinuedFraction[ s][[2]]]]==78]; Select[Range[12000], cf78Q] (* Harvey P. Dale, Jan 16 2022 *)
CROSSREFS
Sequence in context: A254285 A035869 A045198 * A218848 A219427 A297320
KEYWORD
nonn
STATUS
approved