%I #13 Apr 12 2024 03:54:49
%S 0,2,0,0,4,2,2,2,2,4,6,4,2,6,4,6,8,4,4,10,8,6,10,6,8,10,10,8,8,10,12,
%T 16,10,10,14,10,12,12,10,14,18,16,12,18,18,16,18,12,12,18,16,16,20,20,
%U 22,24,18,18,22,20,20,22,16,16,26,26,26,26,22,24,24,24,24,24,26,26,32,24,26,30,28,28,28,26,26,36
%N a(n) = Sum_{i=1..n} d(8*i+5) - Sum_{i=1..n} d(4*i+3), where d(n) = A000005(n).
%H Amiram Eldar, <a href="/A230295/b230295.txt">Table of n, a(n) for n = 1..10000</a>
%H Jorge Luis Cimadevilla Villacorta, <a href="http://www.jstor.org/stable/10.4169/amer.math.monthly.120.09.832">Certain inequalities associated with the divisor function</a>, Amer. Math. Monthly, 120 (2013), 832-837. (Shows that a(n) >= 0.)
%F a(n) = (log(2)/2) * n + O(n^(1/3)*log(n)). - _Amiram Eldar_, Apr 12 2024
%p See A230290.
%t Accumulate[Table[DivisorSigma[0, 8*n + 5] - DivisorSigma[0, 4*n + 3], {n, 1, 100}]] (* _Amiram Eldar_, Apr 12 2024 *)
%o (PARI) vector(100, n, sum(i=1, n, numdiv(8*i+5)) - sum(i=1, n, numdiv(4*i+3))) \\ _Michel Marcus_, Oct 09 2014
%Y Cf. A000005, A230290, A230291, A230292, A230293, A230294, A230296, A230476.
%K nonn
%O 1,2
%A _N. J. A. Sloane_, Oct 17 2013