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 A177114 #13 Jul 31 2017 12:18:20
%S A177114 4,364,3964,39964,399964,3999964,39999964,399999964,3999999964,
%T A177114 39999999964,399999999964,3999999999964,39999999999964,
%U A177114 399999999999964,3999999999999964,39999999999999964,399999999999999964
%N A177114 4*(10^n-9).
%H A177114 Harvey P. Dale, <a href="/A177114/b177114.txt">Table of n, a(n) for n = 1..999</a>
%H A177114 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (11,-10).
%F A177114 G.f. 4*x*(1+80*x) / ( (10*x-1)*(x-1) ). - R. J. Mathar, Aug 24 2011
%F A177114 a(n) = 4*A170955(n). - R. J. Mathar, Aug 24 2011
%t A177114 LinearRecurrence[{11, -10}, {4, 364}, 30] (* or *) Join[{4},Table[ 100*FromDigits[PadRight[{3},n,9]]+64,{n,30}]] (* _Harvey P. Dale_, Jul 31 2017 *)
%K A177114 nonn,easy
%O A177114 1,1
%A A177114 _Vincenzo Librandi_