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%I #11 May 15 2024 01:30:05
%S 25,27,75,81,121,189,225,275,289,297,343,363,405,425,513,529,567,575,
%T 605,621,725,729,825,837,841,867,1025,1029,1053,1089,1161,1175,1225,
%U 1269,1275,1325,1331,1377,1445,1475,1539,1587,1593,1681,1725
%N Odd numbers k such that d(k) does not divide phi(k).
%H Amiram Eldar, <a href="/A015734/b015734.txt">Table of n, a(n) for n = 1..10000</a>
%t Select[Range[1, 2000, 2], !Divisible[EulerPhi[#], DivisorSigma[0, #]] &] (* _Amiram Eldar_, May 15 2024 *)
%o (PARI) is(k) = if(k%2, my(f = factor(k), d = numdiv(f), p = eulerphi(f)); p % d, 0); \\ _Amiram Eldar_, May 15 2024
%Y Intersection of A005408 and A015733.
%Y Cf. A000005 (d), A000010 (phi).
%K nonn,changed
%O 1,1
%A _Robert G. Wilson v_
%E Offset corrected by _Amiram Eldar_, May 15 2024
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