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 A163449 #15 Dec 24 2016 10:57:45
%S A163449 1,11,1010,100100,10001000,1000010000,100000100000,10000001000000,
%T A163449 1000000010000000,100000000100000000,10000000001000000000,
%U A163449 1000000000010000000000,100000000000100000000000,10000000000001000000000000,1000000000000010000000000000
%N A163449 A007582 written in base 2.
%C A163449 For n >= 1, the digits are a "1", (n-1) times "0", a "1", and (n-1) times "0".
%H A163449 G. C. Greubel, <a href="/A163449/b163449.txt">Table of n, a(n) for n = 0..250</a>
%H A163449 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (110, -1000).
%F A163449 a(n) = 10^(2n-1) + 10^(n-1) = A163664(n)/10 for n >= 1.
%F A163449 a(n) = A007088(A007582(n)). - _Michel Marcus_, Dec 24 2016
%t A163449 Join[{1}, Table[10^(2n-1) + 10^(n-1), {n,1,25}]] (* or *) Join[{1}, LinearRecurrence[{110, -1000}, {11, 1010}, 25]] (* _G. C. Greubel_, Dec 24 2016 *)
%o A163449 (PARI) concat([1], for(n=1,50, print1(10^(2*n-1) + 10^(n-1), ", "))) \\ _G. C. Greubel_, Dec 24 2016
%Y A163449 Cf. A007088, A007582.
%K A163449 nonn,base,easy
%O A163449 0,2
%A A163449 _Jaroslav Krizek_, Jul 27 2009
%E A163449 Edited by _R. J. Mathar_, Aug 06 2009