A020366 Numbers k such that the continued fraction for sqrt(k) has period 27.

949, 1109, 1261, 1354, 1361, 1402, 1721, 1889, 1921, 2221, 2561, 2957, 3229, 3821, 4021, 4373, 4481, 4973, 4985, 5473, 5545, 5729, 5765, 5825, 6065, 6322, 6458, 6617, 6730, 6869, 6925, 6938, 7109, 7913, 7985, 8077, 9034, 9146, 9178, 9509, 10061, 10930

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Mathematica

cf27Q[n_]:=Module[{s=Sqrt[n]}, If[IntegerQ[s], 1, Length[ ContinuedFraction[ s][[2]]]] == 27]; Select[Range[11000], cf27Q] (* Harvey P. Dale, Jan 21 2019 *)

Crossrefs

Sequence in context: A192770 A187627 A170830 * A217936 A013532 A108896

Adjacent sequences: A020363 A020364 A020365 * A020367 A020368 A020369

Keyword

nonn

Author

David W. Wilson

Status

approved