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 A048984 As n runs through composite numbers, a(n) = number of nonprime d < n such that GCD(d,n) = 1. 1

%I

%S 1,1,1,3,2,1,2,4,3,1,2,6,4,1,12,5,10,5,1,6,11,7,15,3,8,14,6,2,8,12,10,

%T 3,28,7,19,11,4,26,10,22,14,2,14,20,15,32,5,15,27,8,6,17,21,17,41,6,

%U 12,33,20,4,43,21,35,19,3,50,22,38,24,50,10,19,37

%N As n runs through composite numbers, a(n) = number of nonprime d < n such that GCD(d,n) = 1.

%e 9 is 4th composite number, GCD(9,1)=GCD(9,4)=GCD(9,8)=1, so a(4) = 3.

%Y Cf. A000010, A048983.

%K easy,nonn

%O 0,4

%A _Naohiro Nomoto_

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