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 A065395 Commutator of sigma and phi functions. 11

%I

%S 0,-1,1,-3,5,-1,8,-1,0,1,14,-5,22,4,7,-15,25,-12,31,3,12,6,28,-1,12,

%T 16,23,4,48,-9,56,-5,26,13,44,-44,73,23,36,7,78,-4,76,18,36,12,56,-29,

%U 60,-18,39,18,80,7,66,28,59,32,74,-17,138,40,43,-63,100,-6,112,27,52,12,120,-36,159,55,30,43,136,12,136,3,10,54,102

%N Commutator of sigma and phi functions.

%C a(n)=Sigma[phi(n)]-Phi[Sigma[n]] =A000203[A000010[n]]-A000010[A000203[n]].

%H Harry J. Smith, <a href="/A065395/b065395.txt">Table of n, a(n) for n=1,...,1000</a>

%e n = 13: Sigma[13] = 14, Phi[14] = 6, Phi[13] = 12, Sigma[12] = 28, a(13) = 28-6 = 22.

%o (PARI) { for (n=1, 1000, a=sigma(eulerphi(n)) - eulerphi(sigma(n)); write("b065395.txt", n, " ", a) ) } [From _Harry J. Smith_, Oct 18 2009]

%Y A000203, A000010, A033632

%K sign

%O 1,4

%A Labos E. (labos(AT)ana.sote.hu), Nov 05 2001

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