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%I #20 Sep 08 2022 08:44:54
%S 1,1,18,19,702,721,12959,13680,505439,519119,9330462,9849581,
%T 363915378,373764959,6717919681,7091684640,262018566721,269110251361,
%U 4836892839858,5106003091219,188653004123742,193759007214961,3482556126778079,3676315133993040
%N Denominators of continued fraction convergents to sqrt(359).
%H Vincenzo Librandi, <a href="/A041681/b041681.txt">Table of n, a(n) for n = 0..200</a>
%H <a href="/index/Rec#order_08">Index entries for linear recurrences with constant coefficients</a>, signature (0, 0, 0, 720, 0, 0, 0, -1).
%F G.f.: -(x^2-x-1)*(x^4+19*x^2+1) / (x^8-720*x^4+1). - _Colin Barker_, Nov 21 2013
%F a(n) = 720*a(n-4) - a(n-8) for n>7. - _Vincenzo Librandi_, Dec 22 2013
%t Denominator[Convergents[Sqrt[359], 30]] (* _Harvey P. Dale_, Oct 08 2011 *)
%t CoefficientList[Series[-(x^2 - x-1) (x^4 + 19 x^2 + 1)/(x^8 - 720 x^4 + 1), {x, 0, 30}], x] (* _Vincenzo Librandi_, Dec 22 2013 *)
%o (Magma) I:=[1,1,18,19,702,721,12959,13680]; [n le 8 select I[n] else 720*Self(n-4)-Self(n-8): n in [1..40]]; // _Vincenzo Librandi_, Dec 22 2013
%Y Cf. A041680, A040340.
%K nonn,frac,easy
%O 0,3
%A _N. J. A. Sloane_.
%E More terms from _Colin Barker_, Nov 21 2013
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