A041800 - OEIS

%I #18 Aug 08 2023 12:21:44

%S 20,21,41,554,2811,3365,12906,16271,45448,61719,107167,168886,444939,

%T 4173337,4618276,36501269,114122083,378867518,871857119,2122581756,

%U 7239602387,23841388917,174129324806

%N Numerators of continued fraction convergents to sqrt(421).

%H Vincenzo Librandi, <a href="/A041800/b041800.txt">Table of n, a(n) for n = 0..200</a>

%H <a href="/index/Rec#order_74">Index entries for linear recurrences with constant coefficients</a>, signature (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 88084891393642836, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1).

%F a(n) = 88084891393642836*a(n-37) + a(n-74) for n>73. [_Bruno Berselli_, Nov 09 2013]

%t Numerator[Convergents[Sqrt[421], 30]] (* _Harvey P. Dale_, Mar 28 2012 *)

%Y Cf. A041801.

%K nonn,cofr,frac,easy,less

%O 0,1

%A _N. J. A. Sloane_