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).

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

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