%I #13 Sep 08 2022 08:44:54
%S 1,4,97,392,9505,38412,931393,3763984,91267009,368832020,8943235489,
%T 36141773976,876345810913,3541525017628,85872946233985,
%U 347033309953568,8414672385119617,34005722850432036,824552020795488481
%N Denominators of continued fraction convergents to sqrt(150).
%H Vincenzo Librandi, <a href="/A041275/b041275.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 (0,98,0,-1).
%F G.f.: (1 +4*x -x^2)/(x^4 -98*x^2 +1). - _Vincenzo Librandi_, Dec 14 2013
%F a(n) = 98*a(n-2) - a(n-4). - _Vincenzo Librandi_, Dec 14 2013
%t Denominator[Convergents[Sqrt[150], 30]] (* or *) CoefficientList[Series[(1 + 4 x - x^2)/(x^4 - 98 x^2 + 1), {x, 0, 30}], x] (* _Vincenzo Librandi_, Dec 14 2013 *)
%o (Magma) I:=[1,4,97,392]; [n le 4 select I[n] else 98*Self(n-2)-Self(n-4): n in [1..40]]; // _Vincenzo Librandi_, Dec 14 2013
%Y Cf. A041274.
%K nonn,frac,easy
%O 0,2
%A _N. J. A. Sloane_.