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A336924 a(n) = spf(1+sigma(n)), where spf is the smallest prime factor and sigma is the sum of divisors function.

%I A336924 #6 Aug 10 2020 00:20:07
%S A336924 2,2,5,2,7,13,3,2,2,19,13,29,3,5,5,2,19,2,3,43,3,37,5,61,2,43,41,3,31,
%T A336924 73,3,2,7,5,7,2,3,61,3,7,43,97,3,5,79,73,7,5,2,2,73,3,5,11,73,11,3,7,
%U A336924 61,13,3,97,3,2,5,5,3,127,97,5,73,2,3,5,5,3,97,13,3,11,2,127,5,3,109,7,11,181,7,5,113,13
%N A336924 a(n) = spf(1+sigma(n)), where spf is the smallest prime factor and sigma is the sum of divisors function.
%H A336924 Antti Karttunen, <a href="/A336924/b336924.txt">Table of n, a(n) for n = 1..65537</a>
%H A336924 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>
%F A336924 a(n) = A020639(1+A000203(n)) = A020639(A088580(n)).
%o A336924 (PARI) A336924(n) = (factor((1+sigma(n)))[1, 1]);
%Y A336924 Cf. A000203, A020639, A071189, A088580.
%Y A336924 Cf. also A336691, A336692, A336693, A336694, A336695, A336696.
%K A336924 nonn
%O A336924 1,1
%A A336924 _Antti Karttunen_, Aug 09 2020