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 A166028 #3 Apr 01 2017 15:41:53
%S A166028 4,62,918,5503,29169,252474,7910575,7910575
%N A166028 a(n) is the starting position of the second occurrence of a string of the initial n decimal digits of e in the decimal expansion of e.
%C A166028 The digits 2 7 1 8 2 ... are labeled 0, 1, 2, 3, 4, ...
%C A166028 The next term, a(9), is greater than 50 million. - _Harvey P. Dale_, Apr 01 2017
%e A166028 a(6) is the starting position of the second occurrence of the initial 6 decimals of e. the string '271828' occurs at position 252,474, thus a(6) = 252,474.
%t A166028 Module[{nn=300000,ed},ed=RealDigits[E,10,nn][[1]];Table[ SequencePosition[ ed, Take[ed,n],2][[2]],{n,6}][[All,1]]-1] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Apr 01 2017 *)
%Y A166028 Cf. A001113, A081876
%K A166028 base,nonn
%O A166028 1,1
%A A166028 Steven Lubars (lubars(AT)gmail.com), Oct 04 2009
%E A166028 Two more terms -- a(7) and a(8) -- from _Harvey P. Dale_, Apr 01 2017