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%I #57 Jan 20 2024 11:11:40
%S 5,2,3,6,0,6,7,9,7,7,4,9,9,7,8,9,6,9,6,4,0,9,1,7,3,6,6,8,7,3,1,2,7,6,
%T 2,3,5,4,4,0,6,1,8,3,5,9,6,1,1,5,2,5,7,2,4,2,7,0,8,9,7,2,4,5,4,1,0,5,
%U 2,0,9,2,5,6,3,7,8,0,4,8,9,9,4,1,4,4,1,4,4,0,8,3,7,8,7,8,2,2,7
%N Decimal expansion of (3+sqrt(5))/10.
%C sqrt((3+sqrt(5))/10) = sqrt((phi^2)/5 = (5+sqrt(5))/10 = (3+sqrt(5))/10)+2/10 = 0.723606797... .
%C Essentially the same as A134972, A134945, A098317 and A002163. - _R. J. Mathar_, Sep 30 2013
%C Equals one tenth of the limit of (G(n+2)+G(n+1)+G(n-1)+G(n-2))/G(n), where G(n) is any nonzero sequence satisfying the recurrence G(n+1) = G(n) + G(n-1) including A000032 and A000045, as n --> infinity. - _Richard R. Forberg_, Nov 17 2014
%C 3+sqrt(5) is the perimeter of a golden rectangle with a unit width. - _Amiram Eldar_, May 18 2021
%C Constant x such that x = sqrt(x) - 1/5. - _Andrea Pinos_, Jan 15 2024
%F (3+sqrt(5))/10 = (phi/sqrt(5))^2 = phi^2/5 where phi is the golden ratio.
%e 0.5236067977499...
%t RealDigits[GoldenRatio^2/5,10,120][[1]] (* _Harvey P. Dale_, Dec 02 2014 *)
%Y Cf. A094874, A187798.
%K cons,nonn
%O 0,1
%A _Joost Gielen_, Sep 29 2013
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