cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A355928 Squarefree part of the sum of divisors of n.

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%I A355928 #14 Jul 29 2022 09:53:28
%S A355928 1,3,1,7,6,3,2,15,13,2,3,7,14,6,6,31,2,39,5,42,2,1,6,15,31,42,10,14,
%T A355928 30,2,2,7,3,6,3,91,38,15,14,10,42,6,11,21,78,2,3,31,57,93,2,2,6,30,2,
%U A355928 30,5,10,15,42,62,6,26,127,21,1,17,14,6,1,2,195,74,114,31,35,6,42,5,186,1,14,21,14,3,33,30,5,10
%N A355928 Squarefree part of the sum of divisors of n.
%C A355928 Not multiplicative.
%H A355928 Antti Karttunen, <a href="/A355928/b355928.txt">Table of n, a(n) for n = 1..20000</a>
%H A355928 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>
%F A355928 a(n) = A007913(A000203(n)).
%F A355928 a(n) = A355929(n) + A007913(n).
%o A355928 (PARI) A355928(n) = core(sigma(n));
%o A355928 (Python)
%o A355928 from sympy.ntheory.factor_ import core, divisor_sigma
%o A355928 def A355928(n): return core(divisor_sigma(n)) # _Chai Wah Wu_, Jul 28 2022
%Y A355928 Cf. A000203, A007913, A006532 (positions of 1's), A355929.
%Y A355928 Cf. also A080398.
%K A355928 nonn
%O A355928 1,2
%A A355928 _Antti Karttunen_, Jul 24 2022