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%I #21 Jun 13 2015 00:49:21
%S 1,2,3,8,11,30,491,1012,1503,4018,5521,15060,246481,508022,754503,
%T 2017028,2771531,7560090,123732971,255026032,378759003,1012544038,
%U 1391303041,3795150120,62113704961,128022560042
%N Denominators of continued fraction convergents to sqrt(70).
%H Vincenzo Librandi, <a href="/A041123/b041123.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 (0,0,0,0,0,502,0,0,0,0,0,-1).
%F a(n) = 502*a(n-6)-a(n-12). G.f.: -(x^2-2*x-1)*(x^8+4*x^6+15*x^4+4*x^2+1)/ (x^12-502*x^6+1). [_Colin Barker_, Jul 18 2012]
%t Table[Denominator[FromContinuedFraction[ContinuedFraction[Sqrt[70],n]]],{n,1,50}] (* _Vladimir Joseph Stephan Orlovsky_, Jun 26 2011 *)
%t Denominator[Convergents[Sqrt[70], 30]] (* _Vincenzo Librandi_, Oct 24 2013 *)
%Y Cf. A010522, A041122.
%K nonn,cofr,frac,easy
%O 0,2
%A _N. J. A. Sloane_.