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 A041045 #31 Jul 09 2025 00:11:29
%S A041045 1,3,7,24,247,765,1777,6096,62737,194307,451351,1548360,15934951,
%T A041045 49353213,114641377,393277344,4047414817,12535521795,29118458407,
%U A041045 99890897016,1028027428567,3183973182717,7395973794001
%N A041045 Denominators of continued fraction convergents to sqrt(28).
%H A041045 Vincenzo Librandi, <a href="/A041045/b041045.txt">Table of n, a(n) for n = 0..1000</a>
%H A041045 <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,254,0,0,0,-1).
%F A041045 a(n) = 254*a(n-4)-a(n-8). G.f.: -(x^2-3*x-1)*(x^4+8*x^2+1)/((x^4-16*x^2+1)*(x^4+16*x^2+1)). [_Colin Barker_, Jul 16 2012]
%t A041045 Table[Denominator[FromContinuedFraction[ContinuedFraction[Sqrt[28], n]]], {n, 1, 50}] (* _Vladimir Joseph Stephan Orlovsky_, Mar 18 2011 *)
%t A041045 CoefficientList[Series[- (x^2 - 3 x - 1) (x^4 + 8 x^2 + 1)/((x^4 - 16 x^2 + 1) (x^4 + 16 x^2 + 1)), {x, 0, 30}], x] (* _Vincenzo Librandi_, Oct 23 2013 *)
%t A041045 LinearRecurrence[{0,0,0,254,0,0,0,-1},{1,3,7,24,247,765,1777,6096},30] (* or *) Denominator[Convergents[Sqrt[28],30]] (* _Harvey P. Dale_, Nov 29 2024 *)
%Y A041045 Cf. A010479, A041044.
%K A041045 nonn,cofr,frac,easy
%O A041045 0,2
%A A041045 _N. J. A. Sloane_