%I A070243
%S A070243 2,5,5,9,9,13,13,18,18,20,20,26,26,26,26,32,32,36,36,41,41,43,43,53,53,
%T A070243 53,53,55,55,57,57,64,64,64,64,72,72,72,72,81,81,85,85,88,88,90,90,101,
%U A070243 101,101,101,103,103,105,105,108,108,110,110,119,119,119,119,127,127
%N A070243 Card{ k, phi(k)<=n }.
%D A070243 G. Tenenbaum & Jie Wu, Exercices corriges de theorie analytique et probabiliste 
               des nombres, Collection SMF, Cours specialises, Numero 2, pp. 78-79
%D A070243 S. R. Finch, Mathematical Constants, Cambridge, 2003, pp. 115-118.
%H A070243 T. D. Noe, <a href="b070243.txt">Table of n, a(n) for n=1..1000</a>
%F A070243 lim n ->infinity a(n)/n = zeta(2)zeta(3)/zeta(6) = 1.943596436820759205057...
%F A070243 a(n)=sum(k=1, n, A014197(k)); a(n)=zeta(2)*zeta(3)/zeta(6)*n+O(n*exp(-c*sqrt(log(n))) 
               for a suitable constant c>0. - Benoit Cloitre (benoit7848c(AT)orange.fr), 
               Apr 12 2003
%o A070243 (PARI) for(n=1,150,print1(sum(i=1,100*n,if(sign(eulerphi(i)-n)+1,0,1)+if((eulerphi(i)-n),
               0,1)),","))
%Y A070243 Sequence in context: A152781 A062553 A126357 this_sequence A050175 A059797 
               A034387
%Y A070243 Adjacent sequences: A070240 A070241 A070242 this_sequence A070244 A070245 
               A070246
%K A070243 easy,nonn
%O A070243 1,1
%A A070243 Benoit Cloitre (benoit7848c(AT)orange.fr), May 11 2002