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 A041087 #20 Jul 09 2025 00:15:05
%S A041087 1,7,99,700,9899,69993,989801,6998600,98970201,699790007,9896030299,
%T A041087 69972002100,989504059699,6996500419993,98940509939601,
%U A041087 699580069997200,9893061489900401,69951010499300007,989207208480100499,6994401469860003500,98910827786520149499
%N A041087 Denominators of continued fraction convergents to sqrt(51).
%H A041087 Vincenzo Librandi, <a href="/A041087/b041087.txt">Table of n, a(n) for n = 0..200</a>
%H A041087 <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (0,100,0,-1).
%F A041087 G.f.: -(x^2-7*x-1) / (x^4-100*x^2+1). - _Colin Barker_, Nov 12 2013
%F A041087 a(n) = 100*a(n-2) - a(n-4). - _Vincenzo Librandi_, Dec 11 2013
%t A041087 Table[Denominator[FromContinuedFraction[ContinuedFraction[Sqrt[51], n]]], {n, 1, 50}] (* _Vladimir Joseph Stephan Orlovsky_, Jun 23 2011 *)
%t A041087 CoefficientList[Series[(1 + 7 x - x^2)/(x^4 - 100 x^2 + 1), {x, 0, 30}], x] (* _Vincenzo Librandi_, Dec 11 2013 *)
%o A041087 (Magma) I:=[1, 7, 99, 700]; [n le 4 select I[n] else 100*Self(n-2)-Self(n-4): n in [1..30]]; // _Vincenzo Librandi_, Dec 11 2013
%Y A041087 Cf. A041086, A040043, A020808.
%K A041087 nonn,cofr,easy,frac
%O A041087 0,2
%A A041087 _N. J. A. Sloane_
%E A041087 More terms from _Colin Barker_, Nov 12 2013