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 A277097 #27 Nov 11 2016 21:20:05
%S A277097 3,2,0,-2,4,2,-2,-4,2,-4,4,-2,4,2,-2,2,-4,4,-2,4,2,-4,2,-4,-2,4,2,-2,
%T A277097 -4,2,-2,4,-2,-4,-4,4,-2,2,-2,2,-4,4,4,2,-2,-4,4,2,-2,-4,2,-4,4,4,-2,
%U A277097 2,-4,4,-2,4,2,2,-2,4,2,-2,4,-2,-2,-4,2
%N A277097 a(n) = 5 - (prime(n) mod 10).
%C A277097 Except for a(1)=3 and a(3)=5 the entries are either {-4, -2, 2, 4} and occur in roughly equal ratios. - _Robert G. Wilson v_, Nov 04 2016
%F A277097 a(n) = 5 - A007652(n). - _Robert G. Wilson v_, Nov 04 2016
%e A277097 For n = 10 and prime(10) = 29, so a(10) = 5 - 9 = -4.
%t A277097 f[n_] := 5 - Mod[Prime[n], 10]; Array[f, 71] (* _Robert G. Wilson v_, Nov 04 2016 *)
%o A277097 (PARI) a(n) = my(p=prime(n)); (10*(p\10)+5) - p; \\ _Michel Marcus_, Sep 30 2016
%Y A277097 Cf. A007652, A184593.
%K A277097 sign,easy
%O A277097 1,1
%A A277097 _Dimitris Valianatos_, Sep 29 2016