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A040015 Continued fraction for sqrt(20). 3
4, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8, 2, 8 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Harry J. Smith, Table of n, a(n) for n = 0..20000

G. Xiao, Contfrac

Index entries for continued fractions for constants

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

FORMULA

a(n) = 5 + 3*(-1)^n - 4*(binomial(2*n,n) mod 2), with n>=0. - Paolo P. Lava, Jun 11 2009

EXAMPLE

4.472135954999579392818347337... = 4 + 1/(2 + 1/(8 + 1/(2 + 1/(8 + ...)))). - Harry J. Smith, Jun 03 2009

MAPLE

Digits := 100: convert(evalf(sqrt(N)), confrac, 90, 'cvgts'):

MATHEMATICA

ContinuedFraction[Sqrt[20], 300] (* Vladimir Joseph Stephan Orlovsky, Mar 05 2011 *)

PROG

(PARI) { allocatemem(932245000); default(realprecision, 26000); x=contfrac(sqrt(20)); for (n=0, 20000, write("b040015.txt", n, " ", x[n+1])); } \\ Harry J. Smith, Jun 03 2009

CROSSREFS

Cf. A010476 Decimal expansion. - Harry J. Smith, Jun 03 2009

Sequence in context: A083489 A065464 A201400 * A144926 A153016 A231549

Adjacent sequences:  A040012 A040013 A040014 * A040016 A040017 A040018

KEYWORD

nonn,cofr,easy

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified July 21 02:02 EDT 2019. Contains 325189 sequences. (Running on oeis4.)