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A031419 Numbers n such that continued fraction for sqrt(n) has odd period and a pair of central terms both equal to 6. 1
109, 281, 865, 922, 1277, 1613, 1769, 1933, 2161, 2341, 2789, 3098, 3653, 3961, 4285, 4457, 5065, 5153, 5713, 5858, 5954, 6101, 6458, 6554, 6709, 7129, 7349, 7681, 8237, 8941, 9242, 9305, 9677, 10177, 10498, 10565, 10693, 10762, 11162, 11365, 11698 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

T. D. Noe, Table of n, a(n) for n = 1..1000 [shifted by Georg Fischer, Jun 23 2019]

MATHEMATICA

n = 1; t = {}; While[Length[t] < 50, n++; If[! IntegerQ[Sqrt[n]], c = ContinuedFraction[Sqrt[n]]; len = Length[c[[2]]]; If[OddQ[len] && c[[2, (len + 1)/2]] == 6 && c[[2, (len + 1)/2 - 1]] == 6, AppendTo[t, n]]]]; t (* T. D. Noe, Apr 04 2014; corrected by Georg Fischer, Jun 23 2019 *)

CROSSREFS

Cf. A031404-A031423.

Sequence in context: A193397 A193395 A140036 * A183349 A238682 A070180

Adjacent sequences:  A031416 A031417 A031418 * A031420 A031421 A031422

KEYWORD

nonn

AUTHOR

David W. Wilson

EXTENSIONS

a(1) corrected by T. D. Noe, Apr 04 2014

a(1) = 10 removed by Georg Fischer, Jun 23 2019

STATUS

approved

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Last modified September 26 20:36 EDT 2020. Contains 337374 sequences. (Running on oeis4.)