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%I #8 Jan 07 2018 19:16:17
%S 0,1,0,-2,-2,-6,-4,-10,-10,-10,-6,-16,-16,-28,-22,-14,-14,-30,-30,-48,
%T -48,-36,-26,-48,-48,-48,-36,-36,-36,-64,-72,-102,-102,-82,-66,-42,
%U -42,-78,-60,-36,-36,-76,-88,-130,-130,-130,-108,-154,-154,-154,-154,-122,-122,-174,-174,-134,-134,-98,-70,-128
%N Sum_{d=1..n} phi(d)*mu(d).
%H Charles R Greathouse IV, <a href="/A054585/b054585.txt">Table of n, a(n) for n = 0..10000</a>
%o (PARI) a(n)=my(s); forsquarefree(k=1, n, s += moebius(k)*eulerphi(k)); s \\ _Charles R Greathouse IV_, Jan 07 2018
%o (PARI) first(n)=my(v=vector(n),s); forsquarefree(k=1, n, v[k[1]] = s+=moebius(k)*eulerphi(k)); for(k=4,n, if(v[k]==0, v[k]=v[k-1])); concat(0, v) \\ _Charles R Greathouse IV_, Jan 07 2018
%Y Partial sums of A097945.
%K sign
%O 0,4
%A _N. J. A. Sloane_, Apr 12 2000