A296183 Decimal expansion of (1/2)*sqrt(7 + phi), with the golden section from A001622.

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

Offset: 1

Author

Wolfdieter Lang, Jan 08 2018

Keywords

• nonn
• cons
• easy

Comments

In a regular pentagon inscribed in a unit circle this equals the second largest distance between a vertex and a midpoint of a side. The shortest such distance is (1/2)*sqrt(3 - phi) = (1/2)*A182007 = 0.58778525229..., and the longest 1 + phi/2 = (1/2)*(2 + phi) = (1/2)*A296184 = 1.80901699437...

Examples

			1.467824409521613628098163726467121337542565559888420020510299297523294383...
		

Crossrefs

Cf. A001622, A182007, A296184.

Programs

Mathematica

First@ RealDigits[Sqrt[7 + GoldenRatio]/2, 10, 98] (* Michael De Vlieger, Jan 13 2018 *)

Formula

(1/2)*sqrt(7 + phi). From the comment on the pentagon above this results from sqrt((5/4)^2 + (sqrt(3 - phi)/2 + sqrt(7 - 4*phi)/4)^2).