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A041069 Denominators of continued fraction convergents to sqrt(41). 2
1, 2, 5, 62, 129, 320, 3969, 8258, 20485, 254078, 528641, 1311360, 16264961, 33841282, 83947525, 1041211582, 2166370689, 5373952960, 66653806209, 138681565378, 344016936965, 4266884808958, 8877786554881, 22022457918720, 273147281579521, 568317021077762 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..200

Index entries for linear recurrences with constant coefficients, signature (0,0,64,0,0,1).

FORMULA

G.f.: -(x^4-2*x^3+5*x^2+2*x+1) / (x^6+64*x^3-1). - Colin Barker, Nov 12 2013

a(n) = 64*a(n-3) + a(n-6). - Vincenzo Librandi, Dec 10 2013

MATHEMATICA

Table[Denominator[FromContinuedFraction[ContinuedFraction[Sqrt[41], n]]], {n, 1, 50}] (* Vladimir Joseph Stephan Orlovsky, Mar 21 2011 *)

Denominator[Convergents[Sqrt[41], 30]] (* Vincenzo Librandi, Dec 10 2013 *)

PROG

(MAGMA) I:=[1, 2, 5, 62, 129, 320]; [n le 6 select I[n] else 64*Self(n-3)+Self(n-6): n in [1..30]]; // Vincenzo Librandi, Dec 10 2013

CROSSREFS

Cf. A010495, A041068.

Sequence in context: A294528 A093484 A250195 * A217053 A134590 A012978

Adjacent sequences:  A041066 A041067 A041068 * A041070 A041071 A041072

KEYWORD

nonn,cofr,frac,easy

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Colin Barker, Nov 12 2013

STATUS

approved

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Last modified October 18 08:19 EDT 2021. Contains 348066 sequences. (Running on oeis4.)