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Decimal expansion of (3-phi)^2 = 10 - 5*phi where phi is the golden ratio.
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%I #44 Feb 08 2023 09:32:58

%S 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,

%T 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,

%U 9,7,6,8,5,9,0,5,4,8,7,7,5,1,4

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

%C This is an integer in Q(sqrt(5)). - _Wolfdieter Lang_, Jan 07 2018

%H Ivan Panchenko, <a href="/A187426/b187426.txt">Table of n, a(n) for n = 1..1000</a>

%F (3-phi)^2 = 5/phi^2 = 10 - 5*phi.

%F Smaller root of x^2 - 15x + 25 = 0.

%F Equals 10*A187798-5. - _R. J. Mathar_, Feb 08 2023

%e 1.909830...

%t RealDigits[(3-GoldenRatio)^2,10,120][[1]] (* _Harvey P. Dale_, Jun 30 2017 *)

%o (PARI) (15-5*sqrt(5))/2 \\ _Charles R Greathouse IV_, Aug 31 2013

%Y Cf. A226765.

%Y Apart from the first digit the same as A187798.

%K nonn,cons

%O 1,2

%A _Joost Gielen_, Aug 30 2013

%E Corrected and extended by _Charles R Greathouse IV_, Aug 31 2013