Search: id:A083243
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%I A083243
%S A083243 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,
%T A083243 27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,43,44,45,46,47,48,49,50,
%U A083243 51,52,53,55,56,57,58,59,61,62,63,64,65,67,68,69,71,73,74,75,76,77,79
%N A083243 n is in the sequence iff number of numbers unrelated to n is smaller 
               than that of related ones[=divisors and coprimes] to n: A045763[n]<A073757[n] 
               or A045763[n]<n/2 or A073757[n]>n/2.
%F A083243 d[n]+phi[n]-1<n/2
%e A083243 n=146 is here because it has d=4 divisors,r=72 numbers are coprimes
%e A083243 and u=71 are unrelated: d+r-1=4+72-1=75>n/2=146/2=73>71=u.
%e A083243 n=61455 is here because has 16 divisors and equal number of
%e A083243 coprimes and unrelated numbers u=r=30720: d+r-1-30735>30720.
%t A083243 Do[r=EulerPhi[n]; d=DivisorSigma[0, n]; u=n-r-d+1; If[Greater[n-u, n/
               2], Print[n, {d, r, u}]], {n, 1, 100}]
%Y A083243 Cf. A000005, A000010, A045763, A073757, A020488, A083244, A083245.
%Y A083243 Sequence in context: A122079 A120951 A044923 this_sequence A002837 A056561 
               A085735
%Y A083243 Adjacent sequences: A083240 A083241 A083242 this_sequence A083244 A083245 
               A083246
%K A083243 nonn
%O A083243 1,2
%A A083243 Labos E. (labos(AT)amna1.sote.hu), May 07 2003

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