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A187798
Decimal expansion of (3-phi)/2, where phi is the golden ratio.
8
6, 9, 0, 9, 8, 3, 0, 0, 5, 6, 2, 5, 0, 5, 2, 5, 7, 5, 8, 9, 7, 7, 0, 6, 5, 8, 2, 8, 1, 7, 1, 8, 0, 9, 4, 1, 1, 3, 9, 8, 4, 5, 4, 1, 0, 0, 9, 7, 1, 1, 8, 5, 6, 8, 9, 3, 2, 2, 7, 5, 6, 8, 8, 6, 4, 7, 3, 6, 9, 7, 6, 8, 5, 9, 0, 5, 4, 8, 7, 7, 5, 1, 4, 6, 3, 9, 6, 3, 9, 7, 9, 0, 5, 3, 0, 4, 4, 3, 1, 2, 5, 7, 6, 2, 2
OFFSET
0,1
COMMENTS
This is the height h of the isosceles triangle in a regular pentagon inscribed in the unit circle formed from a diagonal as base and two adjacent pentagon sides. h = sqrt(sqrt(3-phi)^2 - (sqrt(2 + phi)/2)^2) = sqrt(10 - 5*phi)/2 = (3 - phi)/2. - Wolfdieter Lang, Jan 07 2018
FORMULA
Equals (3-phi)/2 = A094874/2 with phi from A001622.
EXAMPLE
0.6909830056250525758977065828171809411398454100971185689322756886473697685905...
MATHEMATICA
RealDigits[(3 - GoldenRatio)/2, 10, 111][[1]] (* or *)
RealDigits[(5 - Sqrt[5])/4, 10, 111][[1]] (* Robert G. Wilson v, Jan 07 2018 *)
PROG
(PARI) (5-sqrt(5))/4 \\ Charles R Greathouse IV, Aug 31 2013
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Joost Gielen, Aug 30 2013
EXTENSIONS
Extended by Charles R Greathouse IV, Aug 31 2013
STATUS
approved