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A363085 Sum of the refactorable unitary divisors of n. 3

%I #60 May 27 2023 13:05:28

%S 1,3,1,1,1,3,1,9,10,3,1,13,1,3,1,1,1,30,1,1,1,3,1,33,1,3,1,1,1,3,1,1,

%T 1,3,1,46,1,3,1,49,1,3,1,1,10,3,1,1,1,3,1,1,1,3,1,65,1,3,1,73,1,3,10,

%U 1,1,3,1,1,1,3,1,90,1,3,1,1,1,3,1,81,1,3,1,97,1,3,1,97

%N Sum of the refactorable unitary divisors of n.

%F a(n) = Sum_{d|n, tau(d)|d, gcd(d,n/d)=1} d.

%t a[n_] := DivisorSum[n, # &, CoprimeQ[#, n/#] && Divisible[#, DivisorSigma[0, #]] &]; Array[a, 100]

%Y Cf. A034444, A336041, A363298.

%K nonn,easy

%O 1,2

%A _Wesley Ivan Hurt_, May 27 2023

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Last modified September 13 05:52 EDT 2024. Contains 375859 sequences. (Running on oeis4.)