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A041286 Numerators of continued fraction convergents to sqrt(156). 2
12, 25, 612, 1249, 30588, 62425, 1528788, 3120001, 76408812, 155937625, 3818911812, 7793761249, 190869181788, 389532124825, 9539640177588, 19468812480001, 476791139697612, 973051091875225, 23830017344703012 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

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.: (12+25*x+12*x^2-x^3)/(1-50*x^2+x^4). - Vincenzo Librandi, Nov 01 2013

a(n) = 50*a(n-2)-a(n-4). - Vincenzo Librandi, Nov 01 2013

MATHEMATICA

Numerator[Convergents[Sqrt[156], 30]] (* or *) CoefficientList[Series[(12 + 25 x + 12 x^2 - x^3)/(1 - 50 x^2 + x^4), {x, 0, 25}], x] (* Vincenzo Librandi, Nov 01 2013 *)

PROG

(MAGMA) I:=[12, 25, 612, 1249]; [n le 4 select I[n] else 50*Self(n-2)-Self(n-4): n in [1..25]]; // Vincenzo Librandi, Nov 01 2013

CROSSREFS

Cf. A041287.

Sequence in context: A041284 A171069 A042193 * A025138 A075689 A054303

Adjacent sequences:  A041283 A041284 A041285 * A041287 A041288 A041289

KEYWORD

nonn,cofr,frac,easy

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified May 27 06:24 EDT 2019. Contains 323599 sequences. (Running on oeis4.)