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 A041149 #20 Jul 09 2025 00:20:29
%S A041149 1,6,109,660,11989,72594,1318681,7984680,145042921,878242206,
%T A041149 15953402629,96598657980,1754729246269,10624974135594,193004263686961,
%U A041149 1168650556257360,21228714276319441,128540936214174006,2334965566131451549,14138334333002883300
%N A041149 Denominators of continued fraction convergents to sqrt(84).
%H A041149 Vincenzo Librandi, <a href="/A041149/b041149.txt">Table of n, a(n) for n = 0..200</a>
%H A041149 <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (0,110,0,-1).
%F A041149 G.f.: -(x^2-6*x-1) / (x^4-110*x^2+1). - _Colin Barker_, Nov 13 2013
%F A041149 a(n) = 110*a(n-2) - a(n-4). - _Vincenzo Librandi_, Dec 11 2013
%t A041149 Denominator/@Convergents[Sqrt[84], 50] (* _Vladimir Joseph Stephan Orlovsky_, Jul 05 2011 *)
%t A041149 CoefficientList[Series[(1 + 6 x - x^2)/(x^4 - 110 x^2 + 1), {x, 0, 30}], x] (* _Vincenzo Librandi_, Dec 11 2013 *)
%o A041149 (Magma) I:=[1, 6, 109, 660]; [n le 4 select I[n] else 110*Self(n-2)-Self(n-4): n in [1..30]]; // _Vincenzo Librandi_, Dec 11 2013
%Y A041149 Cf. A041148, A040074, A020841, A010535.
%K A041149 nonn,cofr,frac,easy
%O A041149 0,2
%A A041149 _N. J. A. Sloane_