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A325815 a(n) = A324213(n) - A034444(n).

%I A325815 #8 May 30 2019 09:43:37
%S A325815 1,2,1,6,2,-2,2,14,10,5,4,10,4,8,4,30,8,22,6,17,10,14,10,16,28,12,16,
%T A325815 -2,12,16,8,62,12,20,18,84,12,26,22,32,16,24,12,38,22,24,22,50,54,76,
%U A325815 16,28,24,36,32,56,34,38,28,48,16,38,44,126,38,40,20,46,24,64,24,118,24,50,54,42,44,48,24,82,118,56,40,88,50,48,36,86,40
%N A325815 a(n) = A324213(n) - A034444(n).
%H A325815 Antti Karttunen, <a href="/A325815/b325815.txt">Table of n, a(n) for n = 1..20000</a>
%H A325815 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>
%F A325815 a(n) = A324213(n) - A034444(n).
%F A325815 a(A000396(n)) < 0 for all n.
%o A325815 (PARI)
%o A325815 A034444(n) = (2^omega(n));
%o A325815 A324213(n) = { my(s=sigma(n)); sum(i=0, s, (1==gcd(n-i, n-(s-i)))); };
%o A325815 A325815(n) = (A324213(n)-A034444(n));
%Y A325815 Cf. A000396, A034444, A324213, A325816.
%K A325815 sign
%O A325815 1,2
%A A325815 _Antti Karttunen_, May 29 2019