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A040002 Continued fraction for sqrt(5). 9
2, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

Decimal expansion of 11/45. - Natan Arie' Consigli Jan 19 2016

LINKS

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

G. Xiao, Contfrac

Index entries for continued fractions for constants

Index to divisibility sequences

FORMULA

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

a(0) = 2, a(n) = 4 n>0. Natan Arie' Consigli Jan 19 2016.

EXAMPLE

2.236067977499789696409173668... = 2 + 1/(4 + 1/(4 + 1/(4 + 1/(4 + ...)))). - Harry J. Smith, Jun 01 2009

MAPLE

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

MATHEMATICA

ContinuedFraction[Sqrt[5], 300] (* Vladimir Joseph Stephan Orlovsky, Mar 04 2011 *)

PROG

(PARI) { allocatemem(932245000); default(realprecision, 26000); x=contfrac(sqrt(5)); for (n=0, 20000, write("b040002.txt", n, " ", x[n+1])); } \\ Harry J. Smith, Jun 01 2009

CROSSREFS

Cf. A002163 Decimal expansion.

Sequence in context: A036264 A105192 A203638 * A151798 A035684 A049111

Adjacent sequences:  A039999 A040000 A040001 * A040003 A040004 A040005

KEYWORD

nonn,cofr,easy,cons

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified December 4 06:30 EST 2016. Contains 278749 sequences.