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 A204815 #12 May 13 2013 01:50:02
%S A204815 1,1,4,2,1,1,1,3,1,4,4,1,1,3,1,2,1,2,4,4,1,1,4,2,1,1,1,3,1,4,1,1,1,3,
%T A204815 1,3,1,2,4,4,1,1,4,2,1,4,1,3,1,4,4,1,1,3,1,1,1,2,4,4,1,1,4,2,1,3,1,3,
%U A204815 1,4,1,1,1,3,1,2,1,2,4,4,1,1,4,2,1
%N A204815 Final nonzero digit of n^n in base 5.
%t A204815 f[0]=1;f[n_]:=Module[{m=n^n},While[Mod[m,5]==0,m=m/5];Mod[m,5]];Table[f[i],{i,0,100}]
%o A204815 (PARI) a(n)=lift(Mod(n/5^valuation(n,5),5)^n) \\ _Charles R Greathouse IV_, Jan 23 2012
%K A204815 nonn,easy,base
%O A204815 0,3
%A A204815 _José María Grau Ribas_, Jan 19 2012