A202276 - OEIS

%I #13 Mar 14 2018 06:35:59

%S 0,1,1,1,2,2,2,2,3,4,5,5,5,5,5,6,7,7,8,8,9,10,11,11,12,13,14,14,15,15,

%T 15,15,16,17,18,18,19,19,19,19,20,20,21,21,22,23,24,24,25,26,27,28,29,

%U 29,30,30,30,31,32,32,33,33,33,34,35,36,37,37,38,39

%N Number of integers k <= n such that sigma(x) = k has no solution, sigma = A000203.

%C Partial sums of A175253.

%H Jaroslav Krizek, <a href="/A202276/b202276.txt">Table of n, a(n) for n = 1..10000</a>

%e a(9) = 3 because sigma(x) = k has no solution for k = 2, 5 and 9.

%Y Cf. A074753, A202277, A202275, A175523, A007369, A007368, A007609.

%K nonn

%O 1,5

%A _Jaroslav Krizek_, Dec 25 2011