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%I #18 Sep 08 2022 08:44:54
%S 1,2,73,148,5401,10950,399601,810152,29565073,59940298,2187415801,
%T 4434771900,161839204201,328113180302,11973913695073,24275940570448,
%U 885907774231201,1796091489032850,65545201379413801,132886494247860452,4849458994302390073
%N Denominators of continued fraction convergents to sqrt(342).
%H Vincenzo Librandi, <a href="/A041647/b041647.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 (0,74,0,-1).
%F G.f.: -(x^2-2*x-1) / (x^4-74*x^2+1). - _Colin Barker_, Nov 20 2013
%F a(n) = 74*a(n-2) - a(n-4) for n>3. - _Vincenzo Librandi_, Dec 22 2013
%t Denominator[Convergents[Sqrt[342], 30]] (* _Harvey P. Dale_, Oct 13 2012 *)
%t CoefficientList[Series[(1 + 2 x - x^2)/(x^4 - 74 x^2 + 1), {x, 0, 30}], x] (* _Vincenzo Librandi_, Dec 22 2013 *)
%o (Magma) I:=[1,2,73,148]; [n le 4 select I[n] else 74*Self(n-2)-Self(n-4): n in [1..40]]; // _Vincenzo Librandi_, Dec 22 2013
%Y Cf. A041646, A040323.
%K nonn,frac,easy
%O 0,2
%A _N. J. A. Sloane_.
%E More terms from _Colin Barker_, Nov 20 2013