login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A020366 Numbers k such that the continued fraction for sqrt(k) has period 27. 0
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 16 14:09 EDT 2021. Contains 348042 sequences. (Running on oeis4.)