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%I #19 Sep 08 2022 08:46:09
%S 0,-1,1,-5,13,-1,33,1,14,7,97,-1,141,25,43,101,253,5,321,37,313,85,
%T 481,1,532,127,569,8,781,27,897,323,299,235,1033,53,1293,301,1297,11,
%U 1597,83,1761,179,173,457,2113,133,2230,971,771,529,2701,163,2737,34,2929,751,3361,11,3597,865,1115
%N Numerator of (n/tau(n) - sigma(n)/n).
%C Numerator of (n/A000005(n) - A000203(n)/n).
%C See A245777 - denominator of (n/tau(n) - sigma(n)/n).
%H Michael De Vlieger, <a href="/A245776/b245776.txt">Table of n, a(n) for n = 1..10000</a>
%F a(n)/A245777(n) < 1 for numbers n in A245779.
%F a(n)/A245777(n) is an integer for numbers n in A245778.
%F a(n) = 1 for n = 3, 8 and 24.
%F a(n) < 0 for n = 2, 4, 6 and 12.
%e For n = 9; a(9) = numerator(9/tau(9) - sigma(9)/9) = numerator(9/3 - 13/9) = numerator(14/9) = 14.
%t a245776[n_Integer] :=
%t Map[Numerator[#/DivisorSigma[0, #] - DivisorSigma[1, #]/#] &,
%t Range[n]]; a245776[63] (* _Michael De Vlieger_, Aug 07 2014 *)
%o (Magma) [Numerator((n/(#[d: d in Divisors(n)]))-(SumOfDivisors(n)/n)): n in [1..1000]]
%o (PARI) vector(150, n, numerator(n/numdiv(n) - sigma(n)/n)) \\ _Derek Orr_, Aug 01 2014
%Y Cf. A000005, A000203, A245777, A245778, A245779, A245782.
%K sign,frac
%O 1,4
%A _Jaroslav Krizek_, Aug 01 2014
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