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A374196 a(n) is the minimum value of A017666 that it obtains among divisors of n larger than 1. By convention a(1) = 1.

%I A374196 #8 Jul 07 2024 17:28:49
%S A374196 1,2,3,2,5,1,7,2,3,2,11,1,13,2,3,2,17,1,19,2,3,2,23,1,5,2,3,1,29,1,31,
%T A374196 2,3,2,5,1,37,2,3,2,41,1,43,2,3,2,47,1,7,2,3,2,53,1,5,1,3,2,59,1,61,2,
%U A374196 3,2,5,1,67,2,3,2,71,1,73,2,3,2,7,1,79,2,3,2,83,1,5,2,3,2,89,1,7,2,3,2,5,1,97,2,3,2
%N A374196 a(n) is the minimum value of A017666 that it obtains among divisors of n larger than 1. By convention a(1) = 1.
%H A374196 Antti Karttunen, <a href="/A374196/b374196.txt">Table of n, a(n) for n = 1..100000</a>
%H A374196 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>
%F A374196 a(1) = 1, and for n > 1, a(n) = Min_{d|n, d>1} A017666(d).
%o A374196 (PARI) A374196(n) = { my(m=0,x); fordiv(n,d,if(d>1, x = denominator(sigma(d)/d); if(!m || x<m, m=x))); if(!m,1,m); };
%Y A374196 Cf. A000203, A017666, A374198 (indices of 1's in this sequence).
%Y A374196 Cf. also A374204.
%K A374196 nonn
%O A374196 1,2
%A A374196 _Antti Karttunen_, Jul 07 2024