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%I #4 Dec 22 2016 23:15:45
%S 1,5,7,9,11,13,15,19,19,21,23,32,27,29,31,39,35,45,39,50,43,45,47,68,
%T 51,53,58,68,59,81,63,79,67,69,71,103,75,77,79,106,83,109,87,104,102,
%U 93,95,140,99,113,103,122,107,138,111,144,115,117,119,184,123
%N a(n) = sigma(n) + phi(n) - mu(n).
%C If n is prime or semiprime, then a(n) = 2n+1.
%F a(n) = A000203(n) + A000010(n) - A008683(n).
%p with(numtheory): a:=n->sigma(n)+phi(n)-mobius(n): seq(a(n), n=1..100);
%t Table[DivisorSigma[1, n] + EulerPhi[n] - MoebiusMu[n], {n, 100}]
%Y Cf. A000010, A000203, A008683.
%K nonn,easy
%O 1,2
%A _Wesley Ivan Hurt_, Dec 22 2016
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