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 A186305 #20 Mar 21 2013 16:21:18
%S A186305 0,1,28,28,1,1,1,1,28,1,28,28,28,1,28,28,1,28,28,28,1,28,1,1,1,1,28,
%T A186305 28,1,0,1,28,28,1,1,1,1,28,1,28,28,28,1,28,28,1,28,28,28,1,28,1,1,1,1,
%U A186305 28,28,1,0,1,28,28,1,1,1,1,28,1,28,28,28,1,28,28,1,28
%N A186305 n^((p-1)/2) (mod p) for p = 29.
%t A186305 p = 29; Table[PowerMod[n, (p-1)/2, p], {n, 0, 100}]
%Y A186305 Cf. A186293-A186304.
%K A186305 nonn
%O A186305 0,3
%A A186305 _Marco Matosic_, Feb 17 2011