%I #18 Sep 08 2022 08:44:55
%S 1,22,969,21340,939929,20699778,911730161,20078763320,884377316241,
%T 19476379720622,857845085023609,18892068250240020,832108848095584489,
%U 18325286726353098778,807144724807631930721,17775509232494255574640
%N Denominators of continued fraction convergents to sqrt(486).
%H Vincenzo Librandi, <a href="/A041927/b041927.txt">Table of n, a(n) for n = 0..200</a>
%H <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (0,970,0,-1).
%F G.f.: -(x^2 -22*x -1) / (x^4 -970*x^2 +1). - _Colin Barker_, Nov 27 2013
%F a(n) = 970*a(n-2) - a(n-4) for n>3. - _Vincenzo Librandi_, Dec 27 2013
%t Denominator[Convergents[Sqrt[486], 30]] (* _Vincenzo Librandi_, Dec 27 2013 *)
%t LinearRecurrence[{0,970,0,-1},{1,22,969,21340},20] (* _Harvey P. Dale_, Feb 06 2017 *)
%o (Magma) I:=[1,22,969,21340]; [n le 4 select I[n] else 970*Self(n-2)-Self(n-4): n in [1..30]]; // _Vincenzo Librandi_, Dec 27 2013
%Y Cf. A041926, A040463.
%K nonn,frac,easy,less
%O 0,2
%A _N. J. A. Sloane_.
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