A042061 - OEIS

%I #16 Jun 13 2015 00:49:38

%S 1,1,2,13,54,67,121,551,3427,3978,7405,344608,352013,696621,4531739,

%T 18823577,23355316,42178893,192070888,1194604221,1386675109,

%U 2581279330,120125524289,122706803619,242832327908,1579700771067,6561635412176,8141336183243

%N Denominators of continued fraction convergents to sqrt(554).

%H Vincenzo Librandi, <a href="/A042061/b042061.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 (0,0,0,0,0,0,0,0,0,0,348586,0,0,0,0,0,0,0,0,0,0,1).

%F G.f.: -(x^20 -x^19 +2*x^18 -13*x^17 +54*x^16 -67*x^15 +121*x^14 -551*x^13 +3427*x^12 -3978*x^11 +7405*x^10 +3978*x^9 +3427*x^8 +551*x^7 +121*x^6 +67*x^5 +54*x^4 +13*x^3 +2*x^2 +x +1) / (x^22 +348586*x^11 -1). - _Colin Barker_, Nov 30 2013

%t Denominator[Convergents[Sqrt[554], 30]] (* _Harvey P. Dale_, Jan 27 2013 *)

%t CoefficientList[Series[-(x^20 - x^19 + 2 x^18 - 13 x^17 + 54 x^16 - 67 x^15 + 121 x^14 - 551 x^13 + 3427 x^12 - 3978 x^11 + 7405 x^10 + 3978 x^9 + 3427 x^8 + 551 x^7 + 121 x^6 + 67 x^5 + 54 x^4 + 13 x^3 + 2 x^2 + x + 1)/(x^22 + 348586 x^11 - 1), {x, 0, 40}], x] (* _Vincenzo Librandi_, Jan 13 2014 *)

%Y Cf. A042060, A040530.

%K nonn,frac,easy

%O 0,3

%A _N. J. A. Sloane_.

%E More terms from _Colin Barker_, Nov 30 2013