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A309875 Cubefree colossally superabundant numbers: cubefree numbers (A004709) k for which there is a positive exponent epsilon such that sigma(k)/k^{1 + epsilon} >= sigma(j)/j^{1 + epsilon} for all cubefree j > 1, so that k attains the maximum value of sigma(k)/k^{1 + epsilon} over the cubefree numbers.

%I A309875 #9 Aug 23 2019 14:37:20
%S A309875 2,6,12,60,180,1260,13860,180180,900900,15315300,290990700,6692786100,
%T A309875 194090796900,6016814703900,42117702927300,1558355008310100,
%U A309875 63892555340714100,2747379879650706300,129126854343583196100,6843723280209909393300,403779673532384654204700
%N A309875 Cubefree colossally superabundant numbers: cubefree numbers (A004709) k for which there is a positive exponent epsilon such that sigma(k)/k^{1 + epsilon} >= sigma(j)/j^{1 + epsilon} for all cubefree j > 1, so that k attains the maximum value of sigma(k)/k^{1 + epsilon} over the cubefree numbers.
%C A309875 This sequence is formed by the largest cubefree divisors (A007948) of the colossally superabundant numbers (A004490).
%H A309875 Paul Erdős and Jean-Louis Nicolas, <a href="https://doi.org/10.24033/bsmf.1793">Répartition des nombres superabondants</a>", Bulletin de la Société Mathématique de France, Vol. 103 (1975), pp. 65-90. See section 5, p. 83.
%Y A309875 Cf. A000203, A004490, A004709, A007948.
%Y A309875 Subsequence of A025487, A220423 and A308618.
%K A309875 nonn
%O A309875 1,1
%A A309875 _Amiram Eldar_, Aug 21 2019