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 A190955 #23 Jan 03 2024 08:51:47
%S A190955 0,1,10,105,1100,11525,120750,1265125,13255000,138875625,1455031250,
%T A190955 15244690625,159722062500,1673444078125,17533051093750,
%U A190955 183697731328125,1924642568750000,20164914344140625,211272356285156250,2213548134572265625,23191843127148437500
%N A190955 a(n) = 10*a(n-1) + 5*a(n-2), with a(0)=0, a(1)=1.
%H A190955 G. C. Greubel, <a href="/A190955/b190955.txt">Table of n, a(n) for n = 0..965</a>
%H A190955 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (10,5).
%F A190955 G.f.: x/(1 - 10*x - 5*x^2). - _R. J. Mathar_, Nov 21 2011
%F A190955 a(n+1) = Sum_{k=0..n} A099089(n,k)*5^k. - _Philippe Deléham_, Nov 21 2011
%t A190955 LinearRecurrence[{10,5}, {0,1}, 50]
%o A190955 (PARI) x='x+O('x^30); concat([0], Vec(x/(1-10*x-5*x^2))) \\ _G. C. Greubel_, Jan 25 2018
%o A190955 (Magma) I:=[0,1]; [n le 2 select I[n] else 10*Self(n-1) + 5*Self(n-2): n in [1..30]]; // _G. C. Greubel_, Jan 25 2018
%K A190955 nonn
%O A190955 0,3
%A A190955 _Vladimir Joseph Stephan Orlovsky_, May 24 2011