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%I A117638 #8 Feb 06 2021 04:59:21
%S A117638 1,2,4,6,8,11,12,16,18,21,22,24,27,29,36,42,44,47,50,54,58,63,66,72,
%T A117638 78,80,81,83,84,85,88,90,94,100,101,105,108,116,117,120,125,126,128,
%U A117638 129,132,135,136,137,144,147,156,160,162,166,168,170,171,173,174,176,180
%N A117638 Numbers k for which the digital root of phi(k) divides k.
%H A117638 Amiram Eldar, <a href="/A117638/b117638.txt">Table of n, a(n) for n = 1..10000</a>
%e A117638 105 is in the sequence because phi(105) = 48 and the digital root of 48 (3) divides 105.
%t A117638 Select[Range[180], Divisible[#, Mod[EulerPhi[#] - 1, 9] + 1] &] (* _Amiram Eldar_, Feb 06 2021 *)
%Y A117638 Cf. A000010, A010888.
%K A117638 nonn,base
%O A117638 1,2
%A A117638 Luc Stevens (lms022(AT)yahoo.com), Apr 09 2006
%E A117638 Offset corrected by _Amiram Eldar_, Feb 06 2021

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