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%I #29 Dec 26 2023 07:02:57
%S 20,801,32060,1283201,51360100,2055687201,82278848140,3293209612801,
%T 131810663360180,5275719744020001,211160600424160220,
%U 8451699736710428801,338279150068841312260,13539617702490362919201,541922987249683358080300
%N Numerators of continued fraction convergents to sqrt(401).
%H Vincenzo Librandi, <a href="/A041760/b041760.txt">Table of n, a(n) for n = 0..200</a>
%H Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a>
%H <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (40,1).
%F a(n) = 40*a(n-1)+a(n-2) for n>1, a(0)=20, a(1)=801. G.f.: (20+x)/(1-40*x-x^2). [_Philippe Deléham_, Nov 23 2008]
%t Numerator[Convergents[Sqrt[401], 30]] (* _Vincenzo Librandi_, Nov 07 2013 *)
%Y Cf. A041761, A040380.
%K nonn,cofr,frac,easy,less
%O 0,1
%A _N. J. A. Sloane_.
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