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!)
A065005 Integers for which the periodic part of the continued fraction for the square root of n begins with 2. 0
2, 6, 12, 19, 20, 29, 30, 41, 42, 54, 55, 56, 70, 71, 72, 88, 89, 90, 107, 108, 109, 110, 129, 130, 131, 132, 153, 154, 155, 156, 178, 179, 180, 181, 182, 206, 207, 208, 209, 210, 236, 237, 238, 239, 240, 267, 268, 269, 270, 271, 272, 301, 302, 303, 304, 305 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..56.

EXAMPLE

The continued fraction for the square root of 12 is 3, {2, 6}.

MATHEMATICA

Select[ Range[500], First[ Last[ ContinuedFraction[ Sqrt[ # ]]]] == 2 & ]

CROSSREFS

Sequence in context: A178480 A053660 A104969 * A299016 A340663 A139084

Adjacent sequences:  A065002 A065003 A065004 * A065006 A065007 A065008

KEYWORD

easy,nonn

AUTHOR

Robert G. Wilson v, Nov 01 2001

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 February 26 17:22 EST 2021. Contains 341632 sequences. (Running on oeis4.)