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%I #12 Nov 12 2018 03:00:09
%S 1,2,1,2,1,2,1,2,1,2,1,4,1,2,2,2,1,3,1,3,2,2,1,4,1,2,1,3,1,5,1,3,2,2,
%T 1,3,1,2,2,3,1,5,1,3,2,2,1,5,1,2,2,3,1,3,1,4,2,2,1,5,1,2,2,5,1,5,1,3,
%U 2,2,1,5,1,2,2,3,1,5,1,4,2,2,1,7,1,2,2,5,1,4,1,3,2,2,1,9,1,2,2,3,1,5,1,6,2
%N Number of k with 1 <= k <= n such that gcd(n,k)=tau(k), where tau is A000005, number of divisors function.
%H Antti Karttunen, <a href="/A074944/b074944.txt">Table of n, a(n) for n = 1..16384</a>
%F Sum_{i=1..n} a(i) seems to be asymptotic to c*n*log(n) with 0.5 < c < 0.6.
%o (PARI) a(n)=sum(k=1,n,if(gcd(n,k)-numdiv(k),0,1))
%Y Cf. A000005.
%K easy,nonn
%O 1,2
%A _Benoit Cloitre_, Oct 05 2002
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