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%I #24 Oct 10 2023 16:20:34
%S 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,
%T 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,
%U 4,7,8,11,13,14,15,13,11,9,7,5,3,1,1,2,3,4
%N Denominators of fractions arranged in "antidiagonal boustrophedon" ordering with equivalent fractions removed: (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, ...).
%H Robert Israel, <a href="/A157813/b157813.txt">Table of n, a(n) for n = 1..10000</a>
%p R:= NULL: count:= 0:
%p for m from 2 while count < 100 do
%p S:= select(t -> igcd(t,m-t)=1, [$1..m-1]);
%p count:= count+nops(S);
%p if m::odd then R:= R, op(S) else R:= R, seq(m-t,t=S) fi;
%p od:
%p R; # _Robert Israel_, Oct 09 2023
%o (Python)
%o from math 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(s - i)
%o for i in range(s, 0, -1):
%o if gcd(i, s + 1 - i) != 1: continue
%o print(s + 1 - i)
%o # _Hiroaki Yamanouchi_, Oct 06 2014
%Y Cf. A157807 (numerators), A038567.
%Y With Cantor's ordering: A020652, A020653, A352911.
%K nonn,frac
%O 1,3
%A _Ron R. King_, Mar 07 2009
%E a(58)-a(83) from _Hiroaki Yamanouchi_, Oct 06 2014
%E Name corrected by _Andrey Zabolotskiy_, Oct 10 2023
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