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A348028 Greatest common divisor of A003415 (arithmetic derivative) and sigma, the sum of divisors function.

%I A348028 #8 May 08 2022 10:34:35
%S A348028 1,1,1,1,1,1,1,3,1,1,1,4,1,3,8,1,1,3,1,6,2,1,1,4,1,3,1,8,1,1,1,1,2,1,
%T A348028 12,1,1,3,8,2,1,1,1,12,39,1,1,4,1,3,4,14,1,3,8,4,2,1,1,4,1,3,1,1,6,1,
%U A348028 1,18,2,1,1,39,1,3,1,20,6,1,1,2,1,1,1,4,2,3,8,20,1,3,4,24,2,1,24,4,1,1,3,7,1,1,1,2,1
%N A348028 Greatest common divisor of A003415 (arithmetic derivative) and sigma, the sum of divisors function.
%H A348028 Antti Karttunen, <a href="/A348028/b348028.txt">Table of n, a(n) for n = 1..65537</a>
%H A348028 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>
%F A348028 a(n) = gcd(A000203(n), A003415(n)).
%o A348028 (PARI)
%o A348028 A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
%o A348028 A348028(n) = gcd(sigma(n), A003415(n));
%Y A348028 Cf. A000203, A003415.
%Y A348028 Cf. also A342413, A342458, A343226.
%K A348028 nonn
%O A348028 1,8
%A A348028 _Antti Karttunen_, Sep 25 2021