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 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

%I

%S 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,

%T 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,

%U 13,11,8,7,4,2,1,1,3,5,7,9,11,13,15,16,15,14

%N 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.

%o (Python)

%o from fractions import gcd

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

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

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

%o ....print(i)

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

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

%o ....print(i)

%o # _Hiroaki Yamanouchi_, Oct 06 2014

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

%K nonn,frac

%O 1,2

%A _Ron R. King_, Mar 07 2009

%E A-number in cross-reference corrected by _R. J. Mathar_, Sep 23 2009

%E a(19)-a(20) corrected and a(58)-a(82) added by _Hiroaki Yamanouchi_, Oct 06 2014

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Last modified June 18 14:52 EDT 2019. Contains 324213 sequences. (Running on oeis4.)