login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A179876 Numbers h such that h and h-1 have same antiharmonic mean of the numbers k < h such that GCD(k, h) = 1. 20
2, 7, 11, 23, 47, 59, 66, 70, 78, 83, 107, 130, 167, 179, 186, 195, 211, 222, 227, 238, 255, 263, 266, 310, 322, 331, 347, 359, 366, 383, 399, 418, 438, 455, 463, 467, 470, 474, 479, 483, 494, 498, 503 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Corresponding values of numbers h-1 see A179875. a(n) = numbers h such that A175505(h) = A175505(h-1). a(n) = numbers h such that A175506(h) = A175506(h-1). Antiharmonic mean B(h) of numbers k such that GCD(k, h) = 1 for numbers h >= 1 and k < h = A053818(n) / A023896(n) = A175505(h) / A175506(h).

LINKS

R. J. Mathar, Table of n, a(n) for n = 1..2047

EXAMPLE

For n=3: a(3) = 11; B(11) = A175505(11) / A175506(11) = 7, B(10) = A175505(10) / A175506(10) = 7.

MAPLE

antiHMeanGcd := proc(h)

        option remember;

        local a023896, a053818, k ;

        a023896 := 0 ;

        a053818 := 0 ;

        for k from 1 to h do

                if igcd(k, h) = 1 then

                        a023896 := a023896+k ;

                        a053818 := a053818+k^2 ;

                end if;

        end do:

        a053818/a023896 ;

end proc:

n := 1:

for h from 2 do

        if antiHMeanGcd(h) = antiHMeanGcd(h-1) then

                printf("%d %d\n", n, h) ;

                n := n+1 ;

        end if;

end do: # R. J. Mathar, Sep 26 2013

CROSSREFS

Cf. A179871 - A179880, A179882 - A179887, A179890, A179891.

Sequence in context: A045374 A168032 A217304 * A088179 A228434 A031873

Adjacent sequences:  A179873 A179874 A179875 * A179877 A179878 A179879

KEYWORD

nonn

AUTHOR

Jaroslav Krizek, Jul 30 2010, Jul 31 2010

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 16 23:58 EDT 2018. Contains 313809 sequences. (Running on oeis4.)