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%I #18 Sep 08 2022 08:44:54
%S 1,1,2,5,17,260,797,1854,2651,4505,137801,142306,280107,702520,
%T 2387667,36517525,111940242,260398009,372338251,632736260,19354426051,
%U 19987162311,39341588362,98670339035,335352605467,5128959421040,15722230868587,36573421158214
%N Denominators of continued fraction convergents to sqrt(243).
%H Vincenzo Librandi, <a href="/A041455/b041455.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 (0,0,0,0,0,0,0,0,0,140452,0,0,0,0,0,0,0,0,0,-1).
%F G.f.: -(x^18 -x^17 +2*x^16 -5*x^15 +17*x^14 -260*x^13 +797*x^12 -1854*x^11 +2651*x^10 -4505*x^9 -2651*x^8 -1854*x^7 -797*x^6 -260*x^5 -17*x^4 -5*x^3 -2*x^2 -x -1) / (x^20 -140452*x^10 +1). - _Colin Barker_, Nov 18 2013
%F a(n) = 140452*a(n-10) - a(n-20) for n>19. - _Vincenzo Librandi_, Dec 18 2013
%t Denominator[Convergents[Sqrt[243], 30]] (* _Vincenzo Librandi_, Dec 18 2013 *)
%o (Magma) I:=[1,1,2,5,17,260,797,1854,2651,4505,137801, 142306,280107,702520,2387667,36517525,111940242, 260398009,372338251,632736260]; [n le 20 select I[n] else 140452*Self(n-10)-Self(n-20): n in [1..40]]; // _Vincenzo Librandi_, Dec 18 2013
%Y Cf. A041454, A040227.
%K nonn,frac,easy
%O 0,3
%A _N. J. A. Sloane_.
%E More terms from _Colin Barker_, Nov 18 2013
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