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%I #10 Oct 19 2017 03:15:02
%S 35,85,133,145,155,175,203,217,245,265,301,323,371,395,425,445,493,
%T 505,553,565,589,595,635,665,679,685,707,725,731,775,805,817,875,889,
%U 899,901,931,973,985,995,1015,1043,1085,1115,1141,1165,1205,1211,1225
%N Numbers n which do not divide any 3^x-2, even though each prime factor of n does divide some 3^x-2.
%H Charles R Greathouse IV, <a href="/A119691/b119691.txt">Table of n, a(n) for n = 1..10000</a>
%e 35 is here because 5 divides 3^3-2 and 7 divides 3^2-2, but 35 divides no 3^x-2.
%o (PARI) isA123239(n)=if(!isprime(n),return(0));if(n<5,return(1)); my(m=Mod(3,n)); while(m!=1,m*=3;if(m==2,return(0)));1
%o is(n)=if(n<9||isprime(n),return(0));my(f=factor(n)[,1]);for(i=1,#f,if(isA123239(f[i]),return(0))); my(m=Mod(3,n)); while(m!=1,m*=3;if(m==2,return(0))); 1 \\ _Charles R Greathouse IV_, Jul 07 2013
%Y Cf. A123239, A131960.
%K nonn
%O 1,1
%A _A.K. Devaraj_, Jul 23 2007
%E Edited by _Don Reble_, Aug 04 2007
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