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 A041180 #28 Dec 26 2023 07:02:24
%S A041180 10,201,4030,80801,1620050,32481801,651256070,13057603201,
%T A041180 261803320090,5249124005001,105244283420110,2110134792407201,
%U A041180 42307940131564130,848268937423689801,17007686688605360150,341002002709530892801
%N A041180 Numerators of continued fraction convergents to sqrt(101).
%H A041180 Vincenzo Librandi, <a href="/A041180/b041180.txt">Table of n, a(n) for n = 0..200</a>
%H A041180 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a>
%H A041180 <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (20,1).
%F A041180 From _Philippe Deléham_, Nov 21 2008: (Start)
%F A041180 a(n) = 20*a(n-1) + a(n-2) for n > 1, a(0)=10, a(1)=201.
%F A041180 G.f.: (10+x)/(1-20*x-x^2). (End)
%t A041180 CoefficientList[Series[(10 + x)/(1 - 20 x - x^2), {x, 0, 30}], x] (* _Vincenzo Librandi_, Oct 30 2013 *)
%t A041180 Numerator[Convergents[Sqrt[101], 20]] (* _Bruno Berselli_, Oct 30 2013 *)
%Y A041180 Cf. A041181.
%K A041180 nonn,cofr,frac,easy
%O A041180 0,1
%A A041180 _N. J. A. Sloane_