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A245278 Decimal expansion of k3, a Diophantine approximation constant such that the conjectured volume of the "critical parallelepiped" is 2^3*k3 (the 3-D analog of A242671). 0
5, 7, 8, 4, 1, 6, 7, 6, 2, 7, 8, 8, 9, 0, 0, 7, 5, 9, 0, 7, 4, 6, 0, 2, 0, 5, 8, 1, 4, 6, 1, 9, 5, 6, 7, 4, 7, 9, 9, 4, 8, 3, 9, 6, 9, 4, 3, 6, 6, 4, 5, 5, 0, 1, 5, 4, 8, 3, 1, 7, 6, 7, 4, 9, 4, 1, 7, 9, 6, 0, 2, 0, 8, 2, 4, 1, 2, 2, 0, 7, 1, 4, 5, 0, 6, 5, 8, 2, 7, 4, 8, 7, 0, 0, 2, 7, 9, 3, 9, 1 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

0,1

REFERENCES

Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, Section 2.23 Diophantine approximation constants, p. 176.

LINKS

Table of n, a(n) for n=0..99.

FORMULA

8/7*cos(2*Pi/7)*cos(Pi/7)^2.

Also equals the positive root of 343*x^3 - 147*x^2 - 28*x - 1.

EXAMPLE

0.578416762788900759074602058146195674799483969436645501548317674941796...

MATHEMATICA

RealDigits[8/7*Cos[2*Pi/7]*Cos[Pi/7]^2, 10, 100] // First

CROSSREFS

Cf. A242671.

Sequence in context: A153104 A233527 A244355 * A155855 A070366 A339986

Adjacent sequences:  A245275 A245276 A245277 * A245279 A245280 A245281

KEYWORD

nonn,cons,easy

AUTHOR

Jean-François Alcover, Jul 16 2014

STATUS

approved

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Last modified January 21 12:58 EST 2022. Contains 350477 sequences. (Running on oeis4.)