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%I #4 Mar 20 2015 17:09:08
%S 0,0,1,0,0,2,0,0,0,2,0,0,0,1,4,0,0,0,0,0,2,0,0,0,0,0,2,6,0,0,0,0,0,1,
%T 0,4,0,0,0,0,0,0,0,2,6,0,0,0,0,0,0,0,0,0,4,0,0,0,0,0,0,0,1,2,4,10,0,0,
%U 0,0,0,0
%N Triangle read by rows: T(m,n) is the cardinality of the set {k in [1,n-1] : gcd(k,n)=m}.
%C A generalization of Euler's phi function: T(1,n)=phi(n).
%e T(2,4)=1 because gcd(1,4)=1, gcd(2,4)=2, gcd(3,4)=1.
%Y Cf. A000010.
%K nonn,easy,tabl
%O 1,6
%A Michele Dondi (bik.mido(AT)tiscalinet.it), Sep 14 2003