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%I #9 Sep 16 2015 13:06:08
%S 6,2,10,2,14,2,3,2,22,2,26,2,6,2,34,2,38,2,3,2,46,2,5,2,3,2,58,2,62,2,
%T 6,2,10,2,74,2,3,2,82,2,86,2,3,2,94,2,7,2,6,2,106,2,5,2,3,2,118,2,122,
%U 2,3,2,10,2,134,2,6,2,142,2,146,2,5,2,14,2,158,2,3,2,166,2,10,2,6,2,178,2
%N a(n) = the smallest positive integer non-coprime to both n and phi(n), where phi(n) is the number of positive integers that are <= n and are coprime to n.
%C Apparently, for p > 2 a prime, we have a(p) = 2*p. If n is not a prime, then let q be the smallest prime dividing n. phi(n) then has (q-1) as factor. Therefore (q-1)q is neither coprime to n nor phi(n). Since q is the smallest prime dividing n, we have a(n) < n. - _Stefan Steinerberger_, Jun 29 2008
%F a(n) = A141327(n, A000010(n)).
%t a = {}; For[n = 3, n < 80, n++, i = 2; While[Min[GCD[i, n], GCD[EulerPhi[n], i]] == 1, i++ ]; AppendTo[a, i]]; a (* _Stefan Steinerberger_, Jun 29 2008 *)
%Y Cf. A141327, A141377, A141378.
%K nonn
%O 3,1
%A _Leroy Quet_, Jun 28 2008
%E More terms from _Stefan Steinerberger_, Jun 29 2008
%E a(78)-a(88) from _Ray Chandler_, Jun 24 2009