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%I #19 Sep 08 2022 08:44:54
%S 1,1,17,18,629,647,10981,11628,406333,417961,7093709,7511670,
%T 262490489,270002159,4582525033,4852527192,169568449561,174420976753,
%U 2960304077609,3134725054362,109540955925917,112675680980279,1912351851610381,2025027532590660
%N Denominators of continued fraction convergents to sqrt(322).
%H Vincenzo Librandi, <a href="/A041609/b041609.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 (0,0,0,646,0,0,0,-1).
%F G.f.: -(x^2-x-1)*(x^4+18*x^2+1) / (x^8-646*x^4+1). - _Colin Barker_, Nov 19 2013
%F a(n) = 646*a(n-4) - a(n-8) for n>7. - _Vincenzo Librandi_, Dec 21 2013
%t Denominator[Convergents[Sqrt[322], 30]] (* _Harvey P. Dale_, Apr 25 2012 *)
%t CoefficientList[Series[-(x^2 - x - 1) (x^4 + 18 x^2 + 1)/(x^8 - 646 x^4 + 1), {x, 0, 30}], x] (* _Vincenzo Librandi_, Dec 21 2013 *)
%o (Magma) I:=[1,1,17,18,629,647,10981,11628]; [n le 8 select I[n] else 646*Self(n-4)-Self(n-8): n in [1..70]]; // _Vincenzo Librandi_, Dec 21 2013
%Y Cf. A041608, A040304.
%K nonn,frac,easy
%O 0,3
%A _N. J. A. Sloane_.
%E More terms from _Colin Barker_, Nov 19 2013
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