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A187426 Decimal expansion of (3-phi)^2 = 10 - 5*phi where phi is the golden ratio. 7
1, 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 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
This is an integer in Q(sqrt(5)). - Wolfdieter Lang, Jan 07 2018
LINKS
FORMULA
(3-phi)^2 = 5/phi^2 = 10 - 5*phi.
Smaller root of x^2 - 15x + 25 = 0.
Equals 10*A187798-5. - R. J. Mathar, Feb 08 2023
EXAMPLE
1.909830...
MATHEMATICA
RealDigits[(3-GoldenRatio)^2, 10, 120][[1]] (* Harvey P. Dale, Jun 30 2017 *)
PROG
(PARI) (15-5*sqrt(5))/2 \\ Charles R Greathouse IV, Aug 31 2013
CROSSREFS
Cf. A226765.
Apart from the first digit the same as A187798.
Sequence in context: A241290 A201298 A029687 * A226765 A132696 A176523
KEYWORD
nonn,cons
AUTHOR
Joost Gielen, Aug 30 2013
EXTENSIONS
Corrected and extended by Charles R Greathouse IV, Aug 31 2013
STATUS
approved

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Last modified July 21 09:16 EDT 2024. Contains 374472 sequences. (Running on oeis4.)