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 A204819 #18 Jan 30 2021 15:14:16
%S A204819 1,1,4,3,4,2,1,7,1,1,1,5,1,4,7,6,7,8,1,1,4,3,4,2,1,7,1,3,1,5,1,4,7,6,
%T A204819 7,8,1,1,4,3,4,2,1,7,1,8,1,5,1,4,7,6,7,8,1,1,4,3,4,2,1,7,1,1,1,5,1,4,
%U A204819 7,6,7,8,1,1,4,3,4,2,1,7,1,1,1,5,1
%N A204819 Final nonzero digit of n^n in base 9.
%H A204819 Harvey P. Dale, <a href="/A204819/b204819.txt">Table of n, a(n) for n = 0..1000</a>
%H A204819 José María Grau and Antonio M. Oller-Marcén, <a href="http://arxiv.org/abs/1203.4066">On the last digit and the last non-zero digit of n^n in base b</a>, arXiv preprint arXiv:1203.4066 [math.NT], 2012.
%t A204819 f[0]=1;f[n_]:=Module[{m=n^n},While[Mod[m,9]==0,m=m/9];Mod[m,9]];y=Table[f[i],{i,0,100}]
%t A204819 Join[{1},Mod[#/10^IntegerExponent[#],10]&/@Table[FromDigits[ IntegerDigits[ n^n,9]],{n,100}]] (* _Harvey P. Dale_, Jan 30 2021 *)
%K A204819 nonn,base
%O A204819 0,3
%A A204819 _José María Grau Ribas_, Jan 19 2012