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%I #23 Sep 08 2022 08:44:54
%S 1,1,2,5,7,12,391,403,794,1991,2785,4776,155617,160393,316010,792413,
%T 1108423,1900836,61935175,63836011,125771186,315378383,441149569,
%U 756527952,24650044033,25406571985,50056616018,125519804021,175576420039,301096224060
%N Denominators of continued fraction convergents to sqrt(275).
%H Vincenzo Librandi, <a href="/A041517/b041517.txt">Table of n, a(n) for n = 0..200</a>
%H <a href="/index/Rec#order_12">Index entries for linear recurrences with constant coefficients</a>, signature (0, 0, 0, 0, 0, 398, 0, 0, 0, 0, 0, -1).
%F G.f.: -(x^4-x^3+2*x^2+x+1)*(x^6-6*x^3-1) / ((x^6-20*x^3+1)*(x^6+20*x^3+1)). - _Colin Barker_, Nov 18 2013
%F a(n) = 398*a(n-6) - a(n-12) for n>11. - _Vincenzo Librandi_, Dec 19 2013
%t Denominator[Convergents[Sqrt[275], 30]] (* _Vincenzo Librandi_, Dec 19 2013 *)
%t LinearRecurrence[{0,0,0,0,0,398,0,0,0,0,0,-1},{1,1,2,5,7,12,391,403,794,1991,2785,4776},30] (* _Harvey P. Dale_, Jul 03 2021 *)
%o (Magma) I:=[1,1,2,5,7,12,391,403,794,1991,2785,4776]; [n le 12 select I[n] else 398*Self(n-6)-Self(n-12): n in [1..30]]; // _Vincenzo Librandi_, Dec 19 2013
%Y Cf. A041516, A040258.
%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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