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%I #2 Mar 31 2012 23:00:51
%S 2,3,5,11,31,97,469,3767,49729
%N Numerator for global rational approximations.
%F a(n) is the smallest integer such that if 0< m1/a(m) < r1/a(r) < 1, m<n and r<n, then there is an integer n1 which satisfies m1/a(m) < n1/a(n) < r1/a(r), but there is no integer n2 with n2/a(n)=m1/a(m) or n2/a(n)=r1/a(r)
%e a(3) is not 4 because 2/4 = 1/2, a(3)=5 because 0 < 1/5 < 1/3 < 2/5 < 1/2 < 3/5 < 2/3 < 4/5 < 1; a(4) is not 7 because if 1/3 < x/7 < 2/5 then x is not an integer
%K nonn
%O 1,1
%A _F. A. González Lahoz_, Jan 24 2003