%I A055212
%S A055212 0,0,0,1,0,1,0,2,1,1,0,3,0,1,1,3,0,3,0,3,1,1,0,5,1,1,2,3,0,4,0,4,1,1,1,
%T A055212 6,0,1,1,5,0,4,0,3,3,1,0,7,1,3,1,3,0,5,1,5,1,1,0,8,0,1,3,5,1,4,0,3,1,4,
%U A055212 0,9,0,1,3,3,1,4,0,7,3,1,0,8,1,1,1,5,0,8,1,3,1,1,1,9,0,3,3,6,0,4,0,5,4
%N A055212 Number of composite divisors of n.
%H A055212 Leroy Quet, <a href="http://www.prism-of-spirals.net/">Home Page</a> 
               (listed in lieu of email address)
%F A055212 a(n)=tau(n)-omega(n)-1, where tau=A000005 and omega=A001221. - Reinhard 
               Zumkeller (reinhard.zumkeller(AT)gmail.com), Jun 13 2003
%e A055212 a[20] = 3 because the composite divisors of 20 are 4, 10, 20.
%t A055212 Table[ Count[ PrimeQ[ Divisors[n] ], False] - 1, {n, 1, 105} ]
%Y A055212 Complement of A083399.
%Y A055212 A033273(n-1) - 1.
%Y A055212 Cf. A137944, A137945.
%Y A055212 Sequence in context: A147602 A114206 A073202 this_sequence A028422 A064577 
               A113949
%Y A055212 Adjacent sequences: A055209 A055210 A055211 this_sequence A055213 A055214 
               A055215
%K A055212 easy,nonn
%O A055212 1,8
%A A055212 Leroy Quet, Jun 23 2000