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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A157807 Numerators of fractions arranged in Cantor's ordering (1/1, 2/1, 1/2, 1/3, 3/1, 4/1, 3/2, 2/3, 1/4, 1/5, 5/1, 6/1, 5/2, ...) with equivalent fractions removed. 4
1, 2, 1, 1, 3, 4, 3, 2, 1, 1, 5, 6, 5, 4, 3, 2, 1, 1, 3, 5, 7, 8, 7, 5, 4, 2, 1, 1, 3, 7, 9, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 1, 5, 7, 11, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 1, 3, 5, 9, 11, 13, 14, 13, 11, 8, 7, 4, 2, 1, 1, 3, 5, 7, 9, 11, 13, 15, 16, 15, 14 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..82.

PROG

(Python)

from fractions import gcd

for s in range(2, 100, 2):

..for i in range(1, s):

....if gcd(i, s - i) != 1: continue

....print(i)

..for i in range(s, 0, -1):

....if gcd(i, s + 1 - i) != 1: continue

....print(i)

# Hiroaki Yamanouchi, Oct 06 2014

CROSSREFS

Cf. A157813, denominators of the same sequence of fractions. Cf. A038566.

Sequence in context: A237498 A319516 A015138 * A100529 A262953 A226209

Adjacent sequences:  A157804 A157805 A157806 * A157808 A157809 A157810

KEYWORD

nonn,frac

AUTHOR

Ron R. King, Mar 07 2009

EXTENSIONS

A-number in cross-reference corrected by R. J. Mathar, Sep 23 2009

a(19)-a(20) corrected and a(58)-a(82) added by Hiroaki Yamanouchi, Oct 06 2014

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 May 25 11:17 EDT 2019. Contains 323539 sequences. (Running on oeis4.)