A041253 - OEIS

%I #16 Sep 08 2022 08:44:54

%S 1,1,3,4,91,95,281,376,8553,8929,26411,35340,803891,839231,2482353,

%T 3321584,75557201,78878785,233314771,312193556,7101573003,7413766559,

%U 21929106121,29342872680,667472305081,696815177761,2061102660603,2757917838364,62735295104611

%N Denominators of continued fraction convergents to sqrt(138).

%H Vincenzo Librandi, <a href="/A041253/b041253.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 (0,0,0,94,0,0,0,-1).

%F G.f.: -(x^2-x-1)*(x^4+4*x^2+1) / (x^8-94*x^4+1). - _Colin Barker_, Nov 14 2013

%F a(n) = 94*a(n-4) - a(n-8). - _Vincenzo Librandi_, Dec 13 2013

%t Denominator[Convergents[Sqrt[138], 30]]  (* _Vincenzo Librandi_, Dec 13 2013 *)

%o (Magma) I:=[1,1,3,4,91,95,281,376]; [n le 8 select I[n] else 94*Self(n-4)-Self(n-8): n in [1..40]]; // _Vincenzo Librandi_, Dec 13 2013

%Y Cf. A041252, A010197.

%K nonn,frac,easy

%O 0,3

%A _N. J. A. Sloane_.

%E More terms from _Colin Barker_, Nov 14 2013