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%I #19 Sep 08 2022 08:44:55
%S 1,1,4,25,79,104,4655,4759,18932,118351,373985,492336,22036769,
%T 22529105,89624084,560273609,1770444911,2330718520,104322059791,
%U 106652778311,424280394724,2652335146655,8381285834689,11033620981344,493860609013825,504894229995169
%N Denominators of continued fraction convergents to sqrt(518).
%H Vincenzo Librandi, <a href="/A041991/b041991.txt">Table of n, a(n) for n = 0..200</a>
%H <a href="/index/Rec#order_12">Index entries for linear recurrences with constant coefficients</a>, signature (0, 0, 0, 0, 0, 4734, 0, 0, 0, 0, 0, -1).
%F G.f.: -(x^10-x^9+4*x^8-25*x^7+79*x^6-104*x^5-79*x^4-25*x^3-4*x^2-x-1) / (x^12-4734*x^6+1). - _Colin Barker_, Nov 28 2013
%F a(n) = 4734*a(n-6) - a(n-12) for n>11. - _Vincenzo Librandi_, Jan 11 2014
%t Denominator[Convergents[Sqrt[518],30]] (* _Harvey P. Dale_, Jan 21 2013 *)
%t CoefficientList[Series[-(x^10 - x^9 + 4 x^8 - 25 x^7 + 79 x^6 - 104 x^5 - 79 x^4 - 25 x^3 - 4 x^2 - x - 1)/(x^12 - 4734 x^6 + 1), {x, 0, 40}], x] (* _Vincenzo Librandi_, Jan 11 2014 *)
%o (Magma) I:=[1,1,4,25,79,104,4655,4759,18932,118351, 373985,492336]; [n le 12 select I[n] else 4734*Self(n-6)-Self(n-12): n in [1..30]]; // _Vincenzo Librandi_, Jan 11 2014
%Y Cf. A041990, A040495.
%K nonn,frac,easy
%O 0,3
%A _N. J. A. Sloane_.
%E More terms from _Colin Barker_, Nov 28 2013
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