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%I #20 Jun 13 2015 00:49:40
%S 1,3,4,11,15,56,2927,8837,11764,32365,44129,164752,8611233,25998451,
%T 34609684,95217819,129827503,484700328,25334244559,76487434005,
%U 101821678564,280130791133,381952469697,1425988200224,74533338881345,225026004844259
%N Denominators of continued fraction convergents to sqrt(690).
%H Vincenzo Librandi, <a href="/A042327/b042327.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 (0,0,0,0,0,2942,0,0,0,0,0,-1).
%F G.f.: -(x^10-3*x^9+4*x^8-11*x^7+15*x^6-56*x^5-15*x^4-11*x^3-4*x^2-3*x-1) / (x^12-2942*x^6+1). - _Colin Barker_, Dec 07 2013
%p convert(sqrt(690), confrac, 30, cvgts): denom(cvgts); # _Wesley Ivan Hurt_, Dec 07 2013
%t Denominator/@Convergents[Sqrt[690], 30] (* _Harvey P. Dale_, Apr 21 2011 *)
%t CoefficientList[Series[-(x^10 - 3 x^9 + 4 x^8 - 11 x^7 + 15 x^6 - 56 x^5 - 15 x^4 - 11 x^3 - 4 x^2 - 3 x - 1)/(x^12 - 2942 x^6 + 1), {x, 0, 30}], x] (* _Vincenzo Librandi_, Jan 20 2014 *)
%Y Cf. A042326, A040663.
%K nonn,frac,easy
%O 0,2
%A _N. J. A. Sloane_.
%E More terms from _Colin Barker_, Dec 07 2013