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 A261872 #17 Sep 08 2022 08:46:13
%S A261872 1,1,2,2,4,2,1,4,1,4,0,4,2,1,3,3,1,1,3,3,2,0,2,3,0,2,3,2,3,3,0,1,0,1,
%T A261872 4,2,1,3,4,1,0,2,2,0,4,2,1,1,2,0,2,4,2,3,0,4,1,3,3,1,0,0,1,2,3,0,1,2,
%U A261872 4,4,0,4,2,1,0,1,0,4,3,2,4,0,2,4,4,2,1,0,3,4,2,4,0,1,2,2,1,2,0,0,0,2,2,3,3
%N A261872 a(n) = phi(n) mod 5, where phi is the Euler totient function.
%H A261872 Antti Karttunen, <a href="/A261872/b261872.txt">Table of n, a(n) for n = 1..16384</a>
%F A261872 a(n) = A000010(n) mod 5 = A010874(A000010(n)).
%t A261872 Table[Mod[EulerPhi[n], 5], {n, 110}]
%o A261872 (Magma) [EulerPhi(n) mod 5: n in [1..110]];
%o A261872 (PARI) a(n) = eulerphi(n) % 5; \\ _Michel Marcus_, Sep 05 2015
%Y A261872 Cf. A000010, A010874, A074942, A084300.
%K A261872 nonn,easy
%O A261872 1,3
%A A261872 _Vincenzo Librandi_, Sep 04 2015
%E A261872 More terms from _Antti Karttunen_, Dec 04 2017