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%I #18 Sep 08 2022 08:44:54
%S 1,5,101,510,10301,52015,1050601,5305020,107151001,541060025,
%T 10928351501,55182817530,1114584702101,5628106328035,113676711262801,
%U 574011662642040,11593909964103601,58543561483160045,1182465139627304501,5970869259619682550
%N Denominators of continued fraction convergents to sqrt(104).
%H Vincenzo Librandi, <a href="/A041187/b041187.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 (0,102,0,-1).
%F G.f.: (1 + 5*x - x^2)/(1 - 102*x^2 + x^4). - _Vincenzo Librandi_, Dec 12 2013
%F a(n) = 102*a(n-2) - a(n-4). - _Vincenzo Librandi_, Dec 12 2013
%t Denominator[Convergents[Sqrt[104], 30]] (* or *) CoefficientList[Series[(1 + 5 x - x^2)/(1 - 102 x^2 + x^4), {x, 0, 30}], x] (* _Vincenzo Librandi_, Dec 12 2013 *)
%t LinearRecurrence[{0,102,0,-1},{1,5,101,510},30] (* _Harvey P. Dale_, Mar 12 2015 *)
%o (Magma) I:=[1,5,101,510]; [n le 4 select I[n] else 102*Self(n-2)-Self(n-4): n in [1..30]]; // _Vincenzo Librandi_, Dec 12 2013
%Y Cf. A041186.
%K nonn,frac,easy
%O 0,2
%A _N. J. A. Sloane_.
%E More terms from _Vincenzo Librandi_, Dec 12 2013