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

Author

Jean-François Alcover, Jul 16 2014

Keywords

• nonn
• cons
• easy

Examples

			0.578416762788900759074602058146195674799483969436645501548317674941796...
		

References

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

Crossrefs

Cf. A242671.

Programs

Mathematica

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

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.