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A020405 Numbers k such that the continued fraction for sqrt(k) has period 66. 0
1699, 2181, 2347, 2371, 2452, 2761, 3076, 3789, 4003, 4169, 4291, 4363, 4456, 4694, 4915, 4987, 5074, 5137, 5201, 5347, 5636, 5651, 5899, 5924, 6041, 6259, 6331, 6634, 6717, 6736, 6884, 7142, 7179, 7198, 7459, 7547, 7556, 7651, 7961, 8079, 8201, 8331 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..42.

MATHEMATICA

cf66Q[n_]:=Module[{s=Sqrt[n]}, If[IntegerQ[s], {1}, Length[ ContinuedFraction[ s] [[2]]]]==66]; Select[Range[9000], cf66Q] (* Harvey P. Dale, Mar 27 2016 *)

CROSSREFS

Cf. A003285.

Sequence in context: A237845 A340170 A083610 * A091368 A263344 A159464

Adjacent sequences:  A020402 A020403 A020404 * A020406 A020407 A020408

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved

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Last modified May 23 16:11 EDT 2022. Contains 353976 sequences. (Running on oeis4.)