This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A081354 #14 May 09 2022 08:36:40 %S A081354 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 A081354 44,45,46,48,50,51,53,54,55,56,61,62,64,66,72,73,76,84,86,87,88,89,91, %U A081354 92,94,95,96,97,98,100,101,105,108,109,111,112,113,114,115,117,118,119,123 %N A081354 Numbers k such that sigma(k^2) modulo 4 = 3. %H A081354 Amiram Eldar, <a href="/A081354/b081354.txt">Table of n, a(n) for n = 1..10000</a> %F A081354 Probably a(n)/n -> 2. %t A081354 Select[Range[150],Mod[DivisorSigma[1,#^2],4]==3&] (* _Harvey P. Dale_, Dec 18 2012 *) %Y A081354 Cf. A000203, A065764. %K A081354 nonn %O A081354 1,1 %A A081354 _Benoit Cloitre_, Apr 20 2003