A187426 Decimal expansion of (3-phi)^2 = 10 - 5*phi where phi is the golden ratio.

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

Offset

1,2

Comments

This is an integer in Q(sqrt(5)). - Wolfdieter Lang, Jan 07 2018

Links

Ivan Panchenko, Table of n, a(n) for n = 1..1000

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

Adjacent sequences: A187423 A187424 A187425 * A187427 A187428 A187429

Keyword

nonn,cons

Author

Joost Gielen, Aug 30 2013

Extensions

Corrected and extended by Charles R Greathouse IV, Aug 31 2013

Status

approved