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 A030600 #11 Dec 30 2018 00:02:21
%S A030600 1,1,1,1,2,1,2,1,1,1,1,1,1,1,2,1,1,1,1,1,1,1,2,1,1,1,1,1,1,1,2,1,1,1,
%T A030600 1,1,1,1,3,1,1,2,1,1,2,1,1,2,1,1,2,1,1,3,2,3,1,1,1,1,1,1,1,2,1,1,1,1,
%U A030600 1,1,1,2,1,1,1,1,1,1,1,2,1,1,1,1,1,1,1,2,1,1
%N A030600 Length of the n-th run of digit 5 in A030588.
%H A030600 Antti Karttunen, <a href="/A030600/b030600.txt">Table of n, a(n) for n = 1..20000</a>
%o A030600 (PARI)
%o A030600 up_to = 20000;
%o A030600 A030600list(up_to,d=5) = { my(v=vector(up_to),ds=List([]),o=1,j=1,rl=0,i=0); while(i<up_to,if(j>#ds,ds=digits(o,6);j=1;o+=2); if(d==ds[j],rl++,if(rl,i++; v[i] = rl; rl=0)); j++); (v); };
%o A030600 v030600 = A030600list(up_to);
%o A030600 A030600(n) = v030600[n]; \\ _Antti Karttunen_, Dec 24 2018
%Y A030600 Cf. A030588, A030596, A030597, A030598, A030599.
%K A030600 nonn,base
%O A030600 1,5
%A A030600 _Clark Kimberling_