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A031680 Numbers n such that continued fraction for sqrt(n) has odd period and central term 92. 0
2117, 53849, 104378, 105674, 172306, 173137, 258185, 360169, 477706, 481861, 771245, 778285, 937465, 1128373, 1327729, 1332341, 1336961, 1339274, 1341589, 1343906, 1563229, 1807177, 1817945, 2051585, 2057317, 2060186, 2063057, 2065930 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..28.

MATHEMATICA

opcf92Q[n_]:=Module[{sr=Sqrt[n], cf, len}, cf=ContinuedFraction[sr]; If[IntegerQ[sr], len=2, len=Length[cf[[2]]]]; OddQ[len]&&cf[[2]][[Ceiling[len/2]]]==92]; Select[Range[2100000], opcf92Q] (* Harvey P. Dale, Mar 29 2014 *)

CROSSREFS

Sequence in context: A324170 A324324 A031770 * A031544 A205660 A205949

Adjacent sequences:  A031677 A031678 A031679 * A031681 A031682 A031683

KEYWORD

nonn

AUTHOR

David W. Wilson

EXTENSIONS

Corrected by and definition modified by Harvey P. Dale, Mar 29 2014

STATUS

approved

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Last modified June 14 12:04 EDT 2021. Contains 345025 sequences. (Running on oeis4.)