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%I #21 Jun 13 2015 00:49:21
%S 1,2,3,20,23,66,947,1960,2907,19402,22309,64020,918589,1901198,
%T 2819787,18819920,21639707,62099334,891030383,1844160100,2735190483,
%U 18255302998,20990493481,60236289960,864298552921,1788833395802,2653131948723,17707625088140
%N Denominators of continued fraction convergents to sqrt(54).
%H Vincenzo Librandi, <a href="/A041093/b041093.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 (0,0,0,0,0,970,0,0,0,0,0,-1).
%F a(n) = 970*a(n-6)-a(n-12). G.f.: -(x^10-2*x^9+3*x^8-20*x^7+23*x^6-66*x^5-23*x^4-20*x^3-3*x^2-2*x-1)/((x^4-10*x^2+1)*(x^8+10*x^6+99*x^4+10*x^2+1)). [_Colin Barker_, Jul 18 2012]
%t Table[Denominator[FromContinuedFraction[ContinuedFraction[Sqrt[54], n]]], {n, 1, 50}] (* _Vladimir Joseph Stephan Orlovsky_, Jun 23 2011 *)
%t Denominator[Convergents[Sqrt[54], 30]] (* _Vincenzo Librandi_, Oct 24 2013 *)
%Y Cf. A010507, A041092.
%K nonn,cofr,frac,easy
%O 0,2
%A _N. J. A. Sloane_.