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%I #23 Sep 08 2022 08:44:55
%S 1,15,901,13530,812701,12204045,733055401,11008035060,661215159001,
%T 9929235420075,596415340363501,8956159340872590,537965975792718901,
%U 8078445796231656105,485244713749692085201,7286749152041612934120,437690193836246468132401
%N Denominators of continued fraction convergents to sqrt(904).
%H Vincenzo Librandi, <a href="/A042747/b042747.txt">Table of n, a(n) for n = 0..200</a>
%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0, 902, 0, -1).
%F a(0)=1, a(1)=15, a(2)=901, a(3)=13530, a(n)=902*a(n-2)-a(n-4). - _Harvey P. Dale_, Sep 25 2013
%F G.f.: -(x^2-15*x-1) / ((x^2-30*x-1)*(x^2+30*x-1)). - _Colin Barker_, Nov 19 2013
%t Denominator[Convergents[Sqrt[904],30]] (* or *) LinearRecurrence[ {0,902,0,-1},{1,15,901,13530},30] (* _Harvey P. Dale_, Sep 25 2013 *)
%o (Magma) I:=[1,15,901,13530]; [n le 4 select I[n] else 902*Self(n-2)-Self(n-4): n in [1..30]]; // _Vincenzo Librandi_, Jan 28 2014
%Y Cf. A042746, A040873.
%K nonn,frac,easy
%O 0,2
%A _N. J. A. Sloane_.
%E Additional term from _Colin Barker_, Nov 19 2013
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