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 A353768 #10 May 16 2022 10:04:08 %S A353768 1,1,2,2,0,2,2,0,2,0,2,0,0,2,0,0,0,2,2,0,0,2,2,0,0,0,2,0,0,0,2,0,0,0, %T A353768 0,0,0,2,0,0,0,0,2,0,0,2,2,0,2,0,0,0,0,2,0,0,0,0,2,0,0,2,0,0,0,0,2,0, %U A353768 0,0,2,0,0,0,0,0,0,0,2,0,2,0,2,0,0,2,0,0,0,0,0,0,0,2,0,0,0,2,0,0,0,0,2,0,0,0,2,0,0,0,0,0,0,0,0,0,0,2,0,0,2 %N A353768 a(n) = phi(n) mod 4; Euler totient function reduced modulo 4. %H A353768 Antti Karttunen, <a href="/A353768/b353768.txt">Table of n, a(n) for n = 1..65537</a> %F A353768 a(n) = A010873(A000010(n)). %o A353768 (PARI) A353768(n) = (eulerphi(n)%4); %Y A353768 Cf. A000010, A010873, A066499 (positions of 2's), A172019 (of 0's). %Y A353768 Cf. also A074942, A261872, A084300, and also A105824. %K A353768 nonn %O A353768 1,3 %A A353768 _Antti Karttunen_, May 15 2022