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A031685 Numbers n such that continued fraction for sqrt(n) has odd period and central term 97. 0
59561, 191050, 193681, 530209, 537514, 680914, 685873, 692513, 857837, 865261, 1248218, 1250453, 1259413, 1471994, 1474421, 1479281, 1481714, 1484149, 1486586, 1491466, 1496354, 1498801, 1722073, 1737853, 1748413, 1988941, 1994585 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..27.

MATHEMATICA

cfop97Q[n_]:=Module[{s=Sqrt[n], cf, len}, If[IntegerQ[s], cf={1, 1}, cf = ContinuedFraction[s][[2]]]; len=Length[cf]; OddQ[len]&&cf[[ (len+1)/2]] ==97]; Select[Range[2*10^6], cfop97Q] (* Harvey P. Dale, Dec 16 2014 *)

CROSSREFS

Sequence in context: A224972 A104919 A135325 * A238077 A043635 A106774

Adjacent sequences:  A031682 A031683 A031684 * A031686 A031687 A031688

KEYWORD

nonn

AUTHOR

David W. Wilson

EXTENSIONS

Corrected by Harvey P. Dale, Dec 16 2014

STATUS

approved

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Last modified May 28 01:34 EDT 2020. Contains 334671 sequences. (Running on oeis4.)