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!)
A031632 Numbers n such that continued fraction for sqrt(n) has odd period and central term 44. 0
485, 12569, 24074, 24698, 60637, 83113, 84269, 111781, 140914, 146213, 180137, 181837, 215737, 217597, 223225, 260629, 262673, 304226, 305329, 306434, 307541, 310874, 311989, 315346, 316469, 363133, 415577, 418157, 420745, 423341, 425945 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..31.

MATHEMATICA

cf44Q[n_]:=Module[{s=Sqrt[n], cf, len}, cf=If[IntegerQ[s], {1, 1}, ContinuedFraction[ s][[2]]]; len=Length[cf]; OddQ[len]&&cf[[(len+1)/2]] == 44]; Select[Range[426000], cf44Q] (* Harvey P. Dale, May 10 2020 *)

CROSSREFS

Sequence in context: A158326 A031722 A156774 * A097767 A031520 A235525

Adjacent sequences:  A031629 A031630 A031631 * A031633 A031634 A031635

KEYWORD

nonn

AUTHOR

David W. Wilson

EXTENSIONS

First term 1937 removed by Georg Fischer, Jun 16 2019

First term (485) added and definition clarified by Harvey P. Dale, May 10 2020

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 July 13 04:01 EDT 2020. Contains 335673 sequences. (Running on oeis4.)