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%I #14 May 09 2022 08:36:40
%S 2,4,5,6,8,12,13,14,15,16,17,18,22,24,28,29,32,35,36,37,38,39,41,42,
%T 44,45,46,48,50,51,53,54,55,56,61,62,64,66,72,73,76,84,86,87,88,89,91,
%U 92,94,95,96,97,98,100,101,105,108,109,111,112,113,114,115,117,118,119,123
%N Numbers k such that sigma(k^2) modulo 4 = 3.
%H Amiram Eldar, <a href="/A081354/b081354.txt">Table of n, a(n) for n = 1..10000</a>
%F Probably a(n)/n -> 2.
%t Select[Range[150],Mod[DivisorSigma[1,#^2],4]==3&] (* _Harvey P. Dale_, Dec 18 2012 *)
%Y Cf. A000203, A065764.
%K nonn
%O 1,1
%A _Benoit Cloitre_, Apr 20 2003