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Denominators of continued fraction convergents to sqrt(411).
2

%I #13 Jun 13 2015 00:49:37

%S 1,3,4,7,11,216,227,443,670,2453,98790,298823,397613,696436,1094049,

%T 21483367,22577416,44060783,66638199,243975380,9825653399,29720935577,

%U 39546588976,69267524553,108814113529,2136735681604,2245549795133,4382285476737,6627835271870

%N Denominators of continued fraction convergents to sqrt(411).

%H Vincenzo Librandi, <a href="/A041781/b041781.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 (0,0,0,0,0,0,0,0,0,99460,0,0,0,0,0,0,0,0,0,-1).

%F G.f.: -(x^18 -3*x^17 +4*x^16 -7*x^15 +11*x^14 -216*x^13 +227*x^12 -443*x^11 +670*x^10 -2453*x^9 -670*x^8 -443*x^7 -227*x^6 -216*x^5 -11*x^4 -7*x^3 -4*x^2 -3*x -1) / (x^20 -99460*x^10 +1). - _Colin Barker_, Nov 24 2013

%F a(n) = 99460*a(n-10) - a(n-20) for n>19. - _Vincenzo Librandi_, Dec 24 2013

%t Denominator[Convergents[Sqrt[411], 30]] (* _Vincenzo Librandi_, Dec 24 2013 *)

%Y Cf. A041780, A040390.

%K nonn,frac,easy

%O 0,2

%A _N. J. A. Sloane_.

%E More terms from _Colin Barker_, Nov 24 2013