cp's OEIS Frontend

A355929 Difference between the squarefree part of the sum of divisors of n and the squarefree part of n.

%I A355929 #8 Jul 29 2022 09:52:48
%S A355929 0,1,-2,6,1,-3,-5,13,12,-8,-8,4,1,-8,-9,30,-15,37,-14,37,-19,-21,-17,
%T A355929 9,30,16,7,7,1,-28,-29,5,-30,-28,-32,90,1,-23,-25,0,1,-36,-32,10,73,
%U A355929 -44,-44,28,56,91,-49,-11,-47,24,-53,16,-52,-48,-44,27,1,-56,19,126,-44,-65,-50,-3,-63,-69,-69,193,1,40,28,16
%N A355929 Difference between the squarefree part of the sum of divisors of n and the squarefree part of n.
%H A355929 Antti Karttunen, <a href="/A355929/b355929.txt">Table of n, a(n) for n = 1..20000</a>
%H A355929 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>
%F A355929 a(n) = A355928(n) - A007913(n) = A007913(A000203(n)) - A007913(n).
%o A355929 (PARI) A355929(n) = (core(sigma(n))-core(n));
%Y A355929 Cf. A000203, A007913, A069070 (positions of 0's), A355928.
%K A355929 sign
%O A355929 1,3
%A A355929 _Antti Karttunen_, Jul 24 2022