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 A217185 #6 Oct 03 2012 14:54:37
%S A217185 1,5,8,13,67,293,293,2576,12790,12790,81874,312865,520061,2063822
%N A217185 a(n) is the number of digits in the decimal representation of the smallest power of 2 that contains n consecutive identical digits.
%C A217185 Number of digits in 2^k is equal to floor(1 + k*log_10(2)).
%t A217185 k = 0; Join[{1}, Table[While[d = IntegerDigits[2^k]; prt = Partition[Differences[d], n - 1, 1]; ! MemberQ[prt, Table[0, {n - 1}]], k++]; Length[d], {n, 2, 8}]] (* _T. D. Noe_, Oct 03 2012 *)
%Y A217185 Cf. A045875, A215732.
%K A217185 nonn,base
%O A217185 1,2
%A A217185 _V. Raman_, Sep 27 2012