cp's OEIS Frontend

A325313 a(n) = A048250(n) - n, where A048250(n) is the sum of squarefree divisors of n.

%I A325313 #17 Apr 22 2019 13:49:22
%S A325313 0,1,1,-1,1,6,1,-5,-5,8,1,0,1,10,9,-13,1,-6,1,-2,11,14,1,-12,-19,16,
%T A325313 -23,-4,1,42,1,-29,15,20,13,-24,1,22,17,-22,1,54,1,-8,-21,26,1,-36,
%U A325313 -41,-32,21,-10,1,-42,17,-32,23,32,1,12,1,34,-31,-61,19,78,1,-14,27,74,1,-60,1,40,-51,-16,19,90,1,-62,-77,44,1,12,23,46
%N A325313 a(n) = A048250(n) - n, where A048250(n) is the sum of squarefree divisors of n.
%H A325313 Antti Karttunen, <a href="/A325313/b325313.txt">Table of n, a(n) for n = 1..16384</a>
%H A325313 Antti Karttunen, <a href="/A325313/a325313.txt">Data supplement: n, a(n) computed for n = 1..65537</a>
%F A325313 a(n) = A048250(n) - n.
%F A325313 a(n) = A325314(n) - A033879(n).
%F A325313 a(A228058(n)) = -A325319(n).
%t A325313 Array[DivisorSum[#, # &, SquareFreeQ] - # &, 86] (* _Michael De Vlieger_, Apr 21 2019 *)
%o A325313 (PARI)
%o A325313 A048250(n) = factorback(apply(p -> p+1,factor(n)[,1]));
%o A325313 A325313(n) = (A048250(n) - n);
%Y A325313 Cf. A033879, A048250, A126795, A228058, A325314, A325315, A325319, A325320.
%K A325313 sign
%O A325313 1,6
%A A325313 _Antti Karttunen_, Apr 21 2019