This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A054585 #8 Jan 07 2018 19:16:17
%S A054585 0,1,0,-2,-2,-6,-4,-10,-10,-10,-6,-16,-16,-28,-22,-14,-14,-30,-30,-48,
%T A054585 -48,-36,-26,-48,-48,-48,-36,-36,-36,-64,-72,-102,-102,-82,-66,-42,
%U A054585 -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 A054585 Sum_{d=1..n} phi(d)*mu(d).
%H A054585 Charles R Greathouse IV, <a href="/A054585/b054585.txt">Table of n, a(n) for n = 0..10000</a>
%o A054585 (PARI) a(n)=my(s); forsquarefree(k=1, n, s += moebius(k)*eulerphi(k)); s \\ _Charles R Greathouse IV_, Jan 07 2018
%o A054585 (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 A054585 Partial sums of A097945.
%K A054585 sign
%O A054585 0,4
%A A054585 _N. J. A. Sloane_, Apr 12 2000