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%I #8 Feb 29 2020 03:33:20
%S 2,4,1,4,1,2,5,1,1,3,4,1,1,1,1,3,1,2,4,3,2,2,1,4,1,1,2,2,3,2,1,1,2,1,
%T 1,1,2,3,2,4,1,2,2,2,1,1,4,1,1,3,1,2,1,2,3,2,3,2,2,1,2,1,3,1,1,4,1,3,
%U 1,2,1,1,3,1,1,1,1,1,1,1,3,1,1,5,1,2,1
%N Distances between multiples of 3 in A000010.
%C Inspired by the question: is n == 1 mod phi(n) for n composite?
%H Amiram Eldar, <a href="/A143973/b143973.txt">Table of n, a(n) for n = 1..10000</a>
%F a(1) = 2 since the first two numbers k such that 3 | phi(k) are 7 and 9, and 9 - 7 = 2.
%t Differences @ Position[EulerPhi[Range[200]], _?(Divisible[#, 3] &)] // Flatten (* _Amiram Eldar_, Feb 29 2020 *)
%Y Cf. A000010, A008585, A066498.
%K nonn
%O 1,1
%A J. Perry (johnandruth(AT)jrperry.orangehome.co.uk), Sep 06 2008
%E Offset corrected and more terms added by _Amiram Eldar_, Feb 29 2020
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