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A020393 Numbers k such that the continued fraction for sqrt(k) has period 54. 0
886, 1747, 1821, 2361, 2404, 2662, 2899, 2998, 3097, 3307, 3412, 3796, 3907, 4061, 4166, 4246, 4377, 4459, 4724, 4769, 4819, 4866, 4911, 5044, 5079, 5147, 5171, 5299, 5531, 5561, 5574, 5599, 5665, 5860, 5889, 5987, 6011, 6059, 6190, 6262, 6265, 6323 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

MATHEMATICA

cf54Q[n_]:=Module[{s=Sqrt[n]}, If[IntegerQ[s], 1, Length[ ContinuedFraction[ s][[2]]]]==54]; Select[Range[6400], cf54Q] (* Harvey P. Dale, Mar 24 2017 *)

CROSSREFS

Cf. A003285.

Sequence in context: A295443 A261760 A031794 * A103811 A190354 A164513

Adjacent sequences:  A020390 A020391 A020392 * A020394 A020395 A020396

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved

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Last modified November 26 21:07 EST 2021. Contains 349344 sequences. (Running on oeis4.)