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A031672 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 84. 0
1765, 143722, 144481, 215417, 405994, 511514, 514378, 515813, 518689, 781897, 796105, 941429, 947258, 951154, 1105226, 1122106, 1126346, 1304893, 1494125, 1499017, 1508825, 1513741, 1711825, 1714442, 1730186, 1732817, 1927633, 1933189, 1941538 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
MATHEMATICA
cf84Q[n_]:=Module[{s=Sqrt[n], c, len}, c=If[IntegerQ[s], {0, 0}, ContinuedFraction[ s][[2]]]; len=Length[c]; OddQ[len]&&c[[(len+1)/2]] == 84]; Select[Range[2*10^6], cf84Q] (* Harvey P. Dale, Jul 31 2016 *)
CROSSREFS
Sequence in context: A343989 A343988 A031762 * A031540 A135795 A206201
KEYWORD
nonn
AUTHOR
EXTENSIONS
Corrected and extended by Harvey P. Dale, Jul 31 2016
STATUS
approved

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Last modified April 18 06:24 EDT 2024. Contains 371769 sequences. (Running on oeis4.)