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A031632
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Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted the two central terms are both 44.
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0
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485, 12569, 24074, 24698, 60637, 83113, 84269, 111781, 140914, 146213, 180137, 181837, 215737, 217597, 223225, 260629, 262673, 304226, 305329, 306434, 307541, 310874, 311989, 315346, 316469, 363133, 415577, 418157, 420745, 423341, 425945
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OFFSET
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1,1
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LINKS
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MATHEMATICA
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cf44Q[n_]:=Module[{s=Sqrt[n], cf, len}, cf=If[IntegerQ[s], {1, 1}, ContinuedFraction[ s][[2]]]; len=Length[cf]; OddQ[len]&&cf[[(len+1)/2]] == 44]; Select[Range[426000], cf44Q] (* Harvey P. Dale, May 10 2020 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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First term (485) added and definition clarified by Harvey P. Dale, May 10 2020
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STATUS
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approved
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