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A348627 Numbers that are both exponential and nonexponential abundant numbers. 1

%I #8 Oct 26 2021 16:52:44

%S 3600,4500,6300,7056,8100,8820,9900,14700,21780,22500,25200,30420,

%T 31500,35280,39600,46800,49500,52020,56700,58500,61200,61740,64980,

%U 68400,69300,76500,77616,81900,82800,85500,88200,89100,91728,95220,97020,103500,104400,105300

%N Numbers that are both exponential and nonexponential abundant numbers.

%H Amiram Eldar, <a href="/A348627/b348627.txt">Table of n, a(n) for n = 1..10000</a>

%e 3600 is a term since A051377(3600) = 7920 > 2*3600 and A160135(3600) = 4573 > 3600.

%t esigma[n_] := Times @@ (Sum[First[#]^d, {d, Divisors[Last[#]]}] &) /@ FactorInteger[n]; Select[Range[10^5], (e = esigma[#]) > 2*# && DivisorSigma[1, #] - e > # &]

%Y Cf. A051377, A160135.

%Y Intersection of A129575 and A348604.

%Y Subsequence of A068403.

%Y Similar sequence: A348523.

%K nonn

%O 1,1

%A _Amiram Eldar_, Oct 26 2021

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Last modified September 9 16:40 EDT 2024. Contains 375765 sequences. (Running on oeis4.)