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A041943 Denominators of continued fraction convergents to sqrt(494). 2
1, 4, 9, 22, 31, 84, 115, 314, 743, 3286, 145327, 584594, 1314515, 3213624, 4528139, 12269902, 16798041, 45865984, 108530009, 479986020, 21227914889, 85391645576, 192011206041, 469414057658, 661425263699, 1792264585056, 2453689848755, 6699644282566 (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, 0, 0, 0, 0, 0, 0, 0, 146070, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1).

FORMULA

G.f.: -(x^18 -4*x^17 +9*x^16 -22*x^15 +31*x^14 -84*x^13 +115*x^12 -314*x^11 +743*x^10 -3286*x^9 -743*x^8 -314*x^7 -115*x^6 -84*x^5 -31*x^4 -22*x^3 -9*x^2 -4*x -1) / (x^20 -146070*x^10 +1). - Colin Barker, Nov 27 2013

a(n) = 146070*a(n-10) - a(n-20) for n>19. - Vincenzo Librandi, Dec 27 2013

MATHEMATICA

Denominator[Convergents[Sqrt[494], 30]] (* Vincenzo Librandi, Dec 27 2013 *)

LinearRecurrence[{0, 0, 0, 0, 0, 0, 0, 0, 0, 146070, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1}, {1, 4, 9, 22, 31, 84, 115, 314, 743, 3286, 145327, 584594, 1314515, 3213624, 4528139, 12269902, 16798041, 45865984, 108530009, 479986020}, 30] (* Harvey P. Dale, May 21 2018 *)

CROSSREFS

Cf. A041942, A040471.

Sequence in context: A076861 A048391 A041743 * A158140 A290647 A105314

Adjacent sequences:  A041940 A041941 A041942 * A041944 A041945 A041946

KEYWORD

nonn,frac,easy

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Colin Barker, Nov 27 2013

STATUS

approved

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Last modified August 3 08:10 EDT 2020. Contains 336197 sequences. (Running on oeis4.)