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%I #16 Jun 26 2018 04:58:55
%S 0,-1,-1,-2,0,-2,2,2,5,5,13,11,21,23,27,30,44,44,60,62,70,76,96,96,
%T 113,121,135,141,167,167,195,205,221,233,253,256,290,304,324,332,370,
%U 374,414,428,446,464,508,514,553,567,595,613,663,673,709,725,757,781,837,841,899,925,955,980,1024,1036,1100,1126,1166
%N a(n) = Sum_{k=1..n} phi(k) - Sum{k=1..n} d(k), where d() is the number of divisors function.
%H Harry J. Smith, <a href="/A063088/b063088.txt">Table of n, a(n) for n = 1..1000</a>
%F a(n) = A002088(n) - A006218(n). - _Michel Marcus_, Jun 26 2018
%t Module[{nn=70,eu,ds},eu=Accumulate[EulerPhi[Range[nn]]];ds=Accumulate[ DivisorSigma[ 0,Range[nn]]];eu-ds] (* _Harvey P. Dale_, Oct 21 2017 *)
%o (PARI) j=[]; for(n=1,200,a=sum(k=1,n,eulerphi(k)); b=sum(k=1,n,numdiv(k)); j=concat(j,a-b)); j
%o (PARI) { a=0; for (n=1, 1000, write("b063088.txt", n, " ", a+=eulerphi(n) - numdiv(n)) ) } \\ _Harry J. Smith_, Aug 17 2009
%Y Cf. A002088, A006218.
%K easy,sign
%O 1,4
%A _Jason Earls_, Aug 06 2001
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