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%I #16 Sep 08 2022 08:44:54
%S 1,1,6,13,71,84,2087,2171,12942,28055,153217,181272,4503745,4685017,
%T 27928830,60542677,330642215,391184892,9719079623,10110264515,
%U 60270402198,130651068911,713525746753,844176815664,20973769322689,21817946138353
%N Denominators of continued fraction convergents to sqrt(165).
%H Vincenzo Librandi, <a href="/A041305/b041305.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 (0,0,0,0,0,2158,0,0,0,0,0,-1).
%F G.f.: -(x^10 -x^9 +6*x^8 -13*x^7 +71*x^6 -84*x^5 -71*x^4 -13*x^3 -6*x^2 -x -1) / ((x^4 -13*x^2 +1)*(x^8 +13*x^6 +168*x^4 +13*x^2 +1)). - _Colin Barker_, Nov 15 2013
%F a(n) = 2158*a(n-6) - a(n-12). - _Vincenzo Librandi_, Dec 15 2013
%t Denominator[Convergents[Sqrt[165], 30]] (* _Vincenzo Librandi_, Dec 15 2013 *)
%o (Magma) I:=[1,1,6,13,71,84,2087,2171,12942,28055,153217, 181272]; [n le 12 select I[n] else 2158*Self(n-6)-Self(n-12): n in [1..40]]; // _Vincenzo Librandi_, Dec 15 2013
%Y Cf. A041304, A010213, A178592.
%K nonn,frac,easy
%O 0,3
%A _N. J. A. Sloane_.
%E More terms from _Colin Barker_, Nov 15 2013
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