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 A179179 a(n) = phi(n) - omega(n) = A000010(n) - A001221(n). 2

%I

%S 1,0,1,1,3,0,5,3,5,2,9,2,11,4,6,7,15,4,17,6,10,8,21,6,19,10,17,10,27,

%T 5,29,15,18,14,22,10,35,16,22,14,39,9,41,18,22,20,45,14,41,18,30,22,

%U 51,16,38,22,34,26,57,13,59,28,34,31,46,17,65,30,42,21,69,22,71,34,38,34,58

%N a(n) = phi(n) - omega(n) = A000010(n) - A001221(n).

%C a(n) is the number of positive integers which are coprime to n minus the number of distinct primes dividing n.

%H Alois P. Heinz, <a href="/A179179/b179179.txt">Table of n, a(n) for n = 1..10000</a>

%H Peter Luschny, Blog on OEIS, <a href="http://oeis.org/wiki/User:Peter_Luschny/EulerTotient"> Euler's totient function</a>

%F a(n) = phi(n) - omega(n), by definition.

%e a(7) = phi(7) - omega(7) = card({1,2,3,4,5,6}) - card({7}) = 6 - 1 = 5

%p with(numtheory): a := n -> phi(n) - nops(factorset(n));

%t Table[EulerPhi[n] - PrimeNu[n], {n,1,50}] (* _G. C. Greubel_, Apr 23 2017 *)

%Y Cf. A000010, A001221, A057859.

%K nonn

%O 1,5

%A _Peter Luschny_, Jun 30 2010

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Last modified December 16 19:11 EST 2018. Contains 318188 sequences. (Running on oeis4.)