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A202275 Differences between A074753 (number of integers k such that sigma(k) <= n) and A202276 (number of integers k <= n such that sigma(x) = k has no solution); sigma = A000203.

%I A202275 #13 Sep 23 2015 07:26:32
%S A202275 1,0,1,2,1,2,3,4,3,2,1,3,4,5,6,5,4,6,5,6,5,4,3,6,5,4,3,4,3,4,6,8,7,6,
%T A202275 5,6,5,6,7,8,7,10,9,10,9,8,7,10,9,8,7,6,5,7,6,8,9,8,7,10,9,10,11,10,9,
%U A202275 8,7,8,7,6,5,10,9,10,9,8,7,8,7,9,8,7,6,9
%N A202275 Differences between A074753 (number of integers k such that sigma(k) <= n) and A202276 (number of integers k <= n such that sigma(x) = k has no solution); sigma = A000203.
%C A202275 Conjectures: Max a(n) = 15 for n = 195, 403, 434. For  n >= 687, a(n) < 0.
%C A202275 First term < 0: a(538) = -1.
%H A202275 Jaroslav Krizek, <a href="/A202275/b202275.txt">Table of n, a(n) for n = 1..10000</a>
%F A202275 a(n) = A074753(n) - A202276(n).
%Y A202275 Cf. A074753, A202277, A202276, A175523, A007369, A007368, A007609.
%K A202275 sign
%O A202275 1,4
%A A202275 _Jaroslav Krizek_, Dec 25 2011