

A157697


Decimal expansion of sqrt(2/3).


3



8, 1, 6, 4, 9, 6, 5, 8, 0, 9, 2, 7, 7, 2, 6, 0, 3, 2, 7, 3, 2, 4, 2, 8, 0, 2, 4, 9, 0, 1, 9, 6, 3, 7, 9, 7, 3, 2, 1, 9, 8, 2, 4, 9, 3, 5, 5, 2, 2, 2, 3, 3, 7, 6, 1, 4, 4, 2, 3, 0, 8, 5, 5, 7, 5, 0, 3, 2, 0, 1, 2, 5, 8, 1, 9, 1, 0, 5, 0, 0, 8, 8, 4, 6, 6, 1, 9, 8, 1, 1, 0, 3, 4, 8, 8, 0, 0, 7, 8, 2, 7, 2, 8, 6, 4
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OFFSET

0,1


COMMENTS

Equals sum_{n=0..infinity} (1)^n*binomial(2n,n)/8^n = 1/A115754 . Averaging this constant with sqrt(2) = A002193 = sum_{n=0..inf} binomial(2n,n)/8^n yields A145439.
Height (from a vertex to the opposite face) of regular tetrahedron with unit edge.  Stanislav Sykora, May 31 2012


REFERENCES

Jolley, Summation of Series, Dover (1961) eq. (168) on page 32.


LINKS

Table of n, a(n) for n=0..104.
D. H. Lehmer, Interesting series involving the Central Binomial Coefficient, Am. Math. Monthly 92, no 7 (1985) 449457.


FORMULA

= 1(1/2)/2 +(1*3)/(2*4)/2^2  (1*3*5)/(2*4*6)/2^3+... [Jolley]


EXAMPLE

0.816496580927726056140063577...


MAPLE

evalf(sqrt(2/3)) ;


MATHEMATICA

RealDigits[N[Sqrt[2/3], 200]][[1]] (*From Vladimir Joseph Stephan Orlovsky, Mar 04 2011*)


CROSSREFS

Sequence in context: A033812 A019717 A007404 * A182551 A005486 A010157
Adjacent sequences: A157694 A157695 A157696 * A157698 A157699 A157700


KEYWORD

cons,easy,nonn


AUTHOR

R. J. Mathar, Mar 04 2009


STATUS

approved



