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 A105824 #29 Nov 07 2017 18:31:16
%S A105824 1,3,0,3,2,0,0,3,1,2,0,0,2,0,0,3,2,3,0,2,0,0,0,0,3,2,0,0,2,0,0,3,0,2,
%T A105824 0,3,2,0,0,2,2,0,0,0,2,0,0,0,1,1,0,2,2,0,0,0,0,2,0,0,2,0,0,3,0,0,0,2,
%U A105824 0,0,0,3,2,2,0,0,0,0,0,2,1,2,0,0,0,0,0,0,2,2,0,0,0,0,0,0,2,3,0,1,2,0,0,2,0
%N A105824 a(n) = sigma(n) mod 4.
%H A105824 Antti Karttunen, <a href="/A105824/b105824.txt">Table of n, a(n) for n = 1..16384</a>
%H A105824 <a href="/index/Su#sums_of_divisors">Index entries for sequences related to sums of divisors</a>
%F A105824 a(n) = A010873(A000203(n)). - _Antti Karttunen_, Nov 07 2017
%p A105824 A105824:= n-> (numtheory[sigma](n) mod 4):
%p A105824 seq (A105824(n), n=1..105); # _Jani Melik_, Jan 26 2011
%t A105824 Table[Mod[DivisorSigma[1, n], 4], {n, 100}] (* _Wesley Ivan Hurt_, Nov 07 2017 *)
%o A105824 (PARI) a(n)=sigma(n)%4
%Y A105824 Cf. A000203, A010873, A248150, A072461, A072462, A191217.
%Y A105824 Sequences sigma(n) mod k: A053866 (k=2), A074941 (k=3), A105824 (k=4), A105825 (k=5), A084301 (k=6), A105826 (k=7), A105827 (k=8).
%K A105824 easy,nonn
%O A105824 1,2
%A A105824 _Shyam Sunder Gupta_, May 05 2005