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%I #11 Jun 13 2015 00:49:22
%S 9,28,513,1567,28719,87724,1607751,4910977,90005337,274926988,
%T 5038691121,15391000351,282076697439,861621092668,15791256365463,
%U 48235390189057,884028279768489,2700320229494524,49489792410669921
%N Numerators of continued fraction convergents to sqrt(87).
%H Vincenzo Librandi, <a href="/A041154/b041154.txt">Table of n, a(n) for n = 0..100</a>
%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0,56,0,-1).
%F G.f.: (9 + 28*x + 9*x^2 - x^3) / (1 - 56*x^2 + x^4). [_Bruno Berselli_, Oct 29 2013]
%F a(n) = 56*a(n-2) - a(n-4). [_Bruno Berselli_, Oct 29 2013]
%t Numerator[Convergents[Sqrt[87], 30]] (* _Vincenzo Librandi_, Oct 29 2013 *)
%Y Cf. A010538, A041155.
%K nonn,cofr,frac,easy
%O 0,1
%A _N. J. A. Sloane_.