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%I #17 Sep 08 2022 08:44:54
%S 1,1,5,6,245,251,1249,1500,61249,62749,312245,374994,15312005,
%T 15686999,78060001,93747000,3827940001,3921687001,19514688005,
%U 23436375006,956969688245,980406063251,4878593941249,5859000004500,239238594121249,245097594125749
%N Denominators of continued fraction convergents to sqrt(434).
%H Vincenzo Librandi, <a href="/A041827/b041827.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 (0,0,0,250,0,0,0,-1).
%F G.f.: -(x^2-x-1)*(x^4+6*x^2+1) / (x^8-250*x^4+1). - _Colin Barker_, Nov 25 2013
%F a(n) = 250*a(n-4) - a(n-8) for n>7. - _Vincenzo Librandi_, Dec 25 2013
%t Denominator[Convergents[Sqrt[434], 30]] (* _Vincenzo Librandi_, Dec 25 2013 *)
%t LinearRecurrence[{0,0,0,250,0,0,0,-1},{1,1,5,6,245,251,1249,1500},30] (* _Harvey P. Dale_, Apr 27 2018 *)
%o (Magma) I:=[1,1,5,6,245,251,1249,1500]; [n le 8 select I[n] else 250*Self(n-4)-Self(n-8): n in [1..40]]; // _Vincenzo Librandi_, Dec 25 2013
%Y Cf. A041826, A040413.
%K nonn,frac,easy
%O 0,3
%A _N. J. A. Sloane_.
%E More terms from _Colin Barker_, Nov 25 2013
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