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%I #15 Dec 05 2023 08:12:34
%S -1,-1,-2,1,-4,0,-6,5,1,-2,-10,10,-12,-4,-6,13,-16,15,-18,12,-10,-8,
%T -22,30,1,-10,10,14,-28,12,-30,29,-18,-14,-22,49,-36,-16,-22,40,-40,
%U 12,-42,18,18,-20,-46,70,1,33,-30,20,-52,60,-38,50,-34,-26,-58,78,-60,-28,20,61,-46,12,-66,24,-42,4,-70,117,-72,-34,34,26,-58,12
%N a(n) = A326142(n) - n, where A326142 gives the sum of all other divisors of n except its largest squarefree divisor.
%H Antti Karttunen, <a href="/A326143/b326143.txt">Table of n, a(n) for n = 1..20000</a>
%H <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>.
%F a(n) = A326142(n) - n = (A000203(n)-A007947(n)) - n = A001065(n) - A007947(n).
%F a(n) = A066503(n) - A033879(n).
%F Sum_{k=1..n} a(k) ~ c * n^2 / 2, where c = A013661 - A065463 - 1 = -0.0595081... . - _Amiram Eldar_, Dec 05 2023
%t rad[n_] := Times @@ FactorInteger[n][[;; , 1]]; a[n_] := DivisorSigma[1, n] - rad[n] - n; Array[a, 100] (* _Amiram Eldar_, Dec 05 2023 *)
%o (PARI)
%o A007947(n) = factorback(factorint(n)[, 1]);
%o A326143(n) = (sigma(n)-A007947(n)-n);
%Y Cf. A000203, A001065, A007947, A033879, A066503, A326142, A326144.
%Y Cf. also A326054, A326127.
%Y Cf. A013661, A065463.
%K sign,easy
%O 1,3
%A _Antti Karttunen_, Jun 09 2019
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