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%I #10 Sep 08 2023 17:31:53
%S 1,2,3,4,5,6,7,8,9,10,10,11,12,13,13,14,14,15,16,17,18,19,19,20,20,20,
%T 21,22,23,24,24,25,26,27,27,28,29,29,29,30,30,31,32,33,34,34,34,35,36,
%U 37,37,38,38,39,39,39,40,40,40,41,42,42,43,44,44,45,46,47,47,47,47,48
%N Number of distinct values in the list of divisor-sums {sigma(j) : j=1...n}.
%H T. D. Noe, <a href="/A061069/b061069.txt">Table of n, a(n) for n=1..1000</a>
%F a(n)=Length[Union[Table[DivisorSigma[1, w], {w, 1, n}]]]
%o (Python)
%o from sympy import divisor_sigma
%o def A061069(n): return len({divisor_sigma(i) for i in range(1,n+1)}) # _Chai Wah Wu_, Sep 08 2023
%Y Cf. A000203.
%K nonn
%O 1,2
%A _Labos Elemer_, May 28 2001
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