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A179050 Decimal expansion of 5/(2*sqrt(5+2*sqrt(5))), area of regular pentagram with base edge length 1. 0
8, 1, 2, 2, 9, 9, 2, 4, 0, 5, 8, 2, 2, 6, 5, 8, 1, 5, 3, 8, 9, 6, 7, 8, 5, 3, 0, 5, 3, 7, 8, 3, 6, 1, 6, 2, 3, 8, 7, 2, 5, 8, 6, 7, 8, 8, 0, 3, 6, 8, 7, 7, 5, 0, 7, 6, 9, 5, 1, 1, 7, 9, 7, 8, 4, 1, 6, 8, 2, 2, 5, 2, 4, 0, 1, 8, 6, 2, 3, 7, 0, 8, 0, 6, 7, 1, 9, 3, 3, 8, 6, 1, 7, 4, 1, 2, 6, 2, 6, 2, 0, 4, 2, 5, 9 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

An algebraic number of degree 4: the smaller positive root of 16x^4 - 200x^2 + 125. - Charles R Greathouse IV, Dec 03 2012

LINKS

Table of n, a(n) for n=0..104.

Thomas M. Green, Area of Pentagram

EXAMPLE

0.81229924058226581538967853053783616238725867880368775076951179784168...

MATHEMATICA

a=1; area=5/(2*Sqrt[5+2*Sqrt[5]]); RealDigits[N[area, 20]]

PROG

(PARI) 5/sqrt(20+8*sqrt(5)) \\ Charles R Greathouse IV, Dec 03 2012

CROSSREFS

Cf. A002194, A010502, A102771, A120011, A179047, A179048, A104956.

Sequence in context: A225767 A019763 A307506 * A176458 A222217 A105473

Adjacent sequences:  A179047 A179048 A179049 * A179051 A179052 A179053

KEYWORD

nonn,cons,easy

AUTHOR

Vladimir Joseph Stephan Orlovsky, Jun 26 2010

EXTENSIONS

Offset corrected, keyword:cons inserted by R. J. Mathar, Jun 28 2010

Name corrected by Charles R Greathouse IV, Dec 03 2012

STATUS

approved

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Last modified June 6 13:00 EDT 2020. Contains 334827 sequences. (Running on oeis4.)