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A041455 Denominators of continued fraction convergents to sqrt(243). 2
1, 1, 2, 5, 17, 260, 797, 1854, 2651, 4505, 137801, 142306, 280107, 702520, 2387667, 36517525, 111940242, 260398009, 372338251, 632736260, 19354426051, 19987162311, 39341588362, 98670339035, 335352605467, 5128959421040, 15722230868587, 36573421158214 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

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

Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,0,0,0,0,0,140452,0,0,0,0,0,0,0,0,0,-1).

FORMULA

G.f.: -(x^18 -x^17 +2*x^16 -5*x^15 +17*x^14 -260*x^13 +797*x^12 -1854*x^11 +2651*x^10 -4505*x^9 -2651*x^8 -1854*x^7 -797*x^6 -260*x^5 -17*x^4 -5*x^3 -2*x^2 -x -1) / (x^20 -140452*x^10 +1). - Colin Barker, Nov 18 2013

a(n) = 140452*a(n-10) - a(n-20) for n>19. - Vincenzo Librandi, Dec 18 2013

MATHEMATICA

Denominator[Convergents[Sqrt[243], 30]] (* Vincenzo Librandi, Dec 18 2013 *)

PROG

(MAGMA) I:=[1, 1, 2, 5, 17, 260, 797, 1854, 2651, 4505, 137801, 142306, 280107, 702520, 2387667, 36517525, 111940242, 260398009, 372338251, 632736260]; [n le 20 select I[n] else 140452*Self(n-10)-Self(n-20): n in [1..40]]; // Vincenzo Librandi, Dec 18 2013

CROSSREFS

Cf. A041454, A040227.

Sequence in context: A132198 A269835 A111635 * A081465 A128000 A281312

Adjacent sequences:  A041452 A041453 A041454 * A041456 A041457 A041458

KEYWORD

nonn,frac,easy

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Colin Barker, Nov 18 2013

STATUS

approved

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Last modified April 6 08:44 EDT 2020. Contains 333268 sequences. (Running on oeis4.)