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 A086045 #10 Dec 09 2022 17:12:40
%S A086045 12,11,16,18,20,22,24,26,28,30,191,14,15,54,74,94,114,134,154,174,252,
%T A086045 33,36,37,76,96,116,136,156,176,282,53,55,58,59,98,118,138,158,178,
%U A086045 312,73,75,77,80,81,120,140,160,180,342,93,95,97,99,102,103,142
%N A086045 Position of second occurrence of n in concatenated numbers (A033307, Champernowne constant).
%C A086045 A033307(a(n)) = A000030(n); a(n)>A086044(n);
%C A086045 A033307(a(n)+i) = A033307(A086044(n)+i), 0<=i < A055642(n).
%H A086045 Paul Tek, <a href="/A086045/b086045.txt">Table of n, a(n) for n = 0..10000</a>
%t A086045 Join[{12},Module[{nn=350,cno},cno=Flatten[IntegerDigits/@Range[nn]];Table[ SequencePosition[ cno,IntegerDigits[n],2][[2,1]],{n,60}]]+1] (* _Harvey P. Dale_, Dec 09 2022 *)
%K A086045 nonn,base
%O A086045 0,1
%A A086045 _Reinhard Zumkeller_, Jul 07 2003