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A157813 Denominators 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, 1, 2, 3, 1, 1, 2, 3, 4, 5, 1, 1, 2, 3, 4, 5, 6, 7, 5, 3, 1, 1, 2, 4, 5, 7, 8, 9, 7, 3, 1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 7, 5, 1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 11, 9, 5, 3, 1, 1, 2, 4, 7, 8, 11, 13, 14, 15, 13, 11, 9, 7, 5, 3, 1, 1, 2, 3, 4 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..83.

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(s - i)

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

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

....print(s + 1 - i)

# Hiroaki Yamanouchi, Oct 06 2014

CROSSREFS

Cf. A157807, numerators of fractions in same sequence. Cf. A038567.

Sequence in context: A190593 A276336 A212811 * A111879 A193280 A114732

Adjacent sequences:  A157810 A157811 A157812 * A157814 A157815 A157816

KEYWORD

nonn,frac

AUTHOR

Ron R. King, Mar 07 2009

EXTENSIONS

a(58)-a(83) from Hiroaki Yamanouchi, Oct 06 2014

STATUS

approved

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Last modified May 24 01:29 EDT 2019. Contains 323528 sequences. (Running on oeis4.)