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A041287 Denominators of continued fraction convergents to sqrt(156). 2
1, 2, 49, 100, 2449, 4998, 122401, 249800, 6117601, 12485002, 305757649, 624000300, 15281764849, 31187529998, 763782484801, 1558752499600, 38173842475201, 77906437450002, 1907928341275249, 3893763120000500, 95358243221287249, 194610249562574998 (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 (0,50,0,-1).

FORMULA

G.f.: (1 +2*x -x^2)/(x^4 -50*x^2 +1). - Vincenzo Librandi, Dec 14 2013

a(n) = 50*a(n-2) - a(n-4). - Vincenzo Librandi, Dec 14 2013

MATHEMATICA

Denominator[Convergents[Sqrt[156], 30]] (* or *) CoefficientList[Series[(1 + 2 x - x^2)/(x^4 - 50 x^2 + 1), {x, 0, 30}], x] (* Vincenzo Librandi, Dec 14 2013 *)

LinearRecurrence[{0, 50, 0, -1}, {1, 2, 49, 100}, 30] (* Harvey P. Dale, Aug 05 2015 *)

PROG

(MAGMA) I:=[1, 2, 49, 100]; [n le 4 select I[n] else 50*Self(n-2)-Self(n-4): n in [1..40]]; // Vincenzo Librandi, Dec 14 2013

CROSSREFS

Cf. A041286.

Sequence in context: A280189 A280188 A058845 * A057563 A297819 A297989

Adjacent sequences:  A041284 A041285 A041286 * A041288 A041289 A041290

KEYWORD

nonn,frac,easy

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Vincenzo Librandi, Dec 14 2013

STATUS

approved

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Last modified May 16 14:56 EDT 2022. Contains 353705 sequences. (Running on oeis4.)