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 A163450 #19 Sep 08 2022 08:45:46
%S A163450 100,1100,101000,10010000,1000100000,100001000000,10000010000000,
%T A163450 1000000100000000,100000001000000000,10000000010000000000,
%U A163450 1000000000100000000000,100000000001000000000000,10000000000010000000000000,1000000000000100000000000000
%N A163450 A028403 written in base 2.
%C A163450 The digit pattern is (for n>1): one 1, (n-2) times 0, one 1, and n times 0.
%H A163450 G. C. Greubel, <a href="/A163450/b163450.txt">Table of n, a(n) for n = 1..250</a>
%H A163450 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (110,-1000).
%F A163450 a(n) = 10^(2n-1) + 10^n, for n >= 2.
%F A163450 a(n) = 110*a(n-1) -1000*a(n-2), n>3.
%F A163450 G.f.: 100*x*(1 - 99*x + 800*x^2) / ((-1 + 10*x)*(-1 + 100*x)). - _G. C. Greubel_, Dec 24 2016
%F A163450 a(n) = A007088(A028403(n)). - _Michel Marcus_, Dec 24 2016
%t A163450 Join[{100}, LinearRecurrence[{110, -1000}, {1100, 101000}, 50]] (* or *) Join[{100}, Table[10^(2n-1) + 10^n, {n,1,25}]] (* _G. C. Greubel_, Dec 24 2016 *)
%o A163450 (PARI) Vec(100*x*(1 - 99*x + 800*x^2)/((-1 + 10*x)*(-1 + 100*x)) + O(x^50)) \\ _G. C. Greubel_, Dec 24 2016
%o A163450 (Magma) [100] cat [10^(2*n-1)+10^n: n in [2..20]]; // _Vincenzo Librandi_, Dec 24 2016
%Y A163450 Cf. A007088, A028403.
%K A163450 nonn,easy,base
%O A163450 1,1
%A A163450 _Jaroslav Krizek_, Jul 27 2009
%E A163450 Recurrence added by _R. J. Mathar_, Oct 21 2009