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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A014665 Number of new fractions m/n < 1, where (m,n)=1 and "new" means the value of mn has not occurred before. 5
1, 1, 2, 2, 4, 1, 6, 4, 6, 2, 10, 3, 12, 3, 5, 8, 16, 3, 18, 6, 7, 5, 22, 5, 20, 6, 18, 8, 28, 4, 30, 16, 12, 8, 18, 9, 36, 9, 14, 12, 40, 6, 42, 13, 17, 11, 46, 11, 42, 10, 19, 15, 52, 9, 25, 20, 21, 14, 58, 10, 60, 15, 28, 32, 29, 9, 66, 21, 26, 11, 70, 20, 72, 18, 23, 23, 42, 11, 78, 23, 54 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

REFERENCES

S. W. Golomb, personal communication, Svalbard, Norway, 7/97.

LINKS

Andrew Howroyd, Table of n, a(n) for n = 1..10000 (terms 1..1000 from T. D. Noe)

EXAMPLE

{1}, {1/2}, {1/3,2/3}, {1/4,3/4}, {1/5,...,4/5}, {5/6}, ...

PROG

(PARI) a(n)=if(n==1, 1, sum(i=1, n-1, gcd(i, n) == 1 && 0==sumdiv(i*n, d, my(t=i*n/d); gcd(t, d)==1 && d<n && t<d))) \\ Andrew Howroyd, Nov 16 2018

CROSSREFS

Cf. A027435, A236309.

Sequence in context: A072211 A299020 A070306 * A055035 A235138 A204595

Adjacent sequences:  A014662 A014663 A014664 * A014666 A014667 A014668

KEYWORD

nonn

AUTHOR

N. J. A. Sloane

EXTENSIONS

Example corrected by and more terms from Olivier Gérard, February 1999

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 April 19 10:39 EDT 2019. Contains 322255 sequences. (Running on oeis4.)