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%I #25 Aug 21 2023 10:15:30
%S 1,5,3,8,8,4,1,7,6,8,5,8,7,6,2,6,7,0,1,2,8,5,1,4,5,2,8,8,0,1,8,4,5,4,
%T 9,1,2,0,0,3,3,5,1,0,7,1,7,6,8,8,9,6,2,1,3,5,1,9,5,7,8,1,2,5,1,8,7,4,
%U 3,1,6,4,4,2,4,7,5,4,5,4,5,9,2,2,7,2,9,6,8,6,0,8,3,3,5,5,2,7,1,7,6,3,5,9,5
%N Decimal expansion of sqrt(5 + 2*sqrt(5))/2, the height of a regular pentagon and midradius of an icosidodecahedron with side length 1.
%C Icosidodecahedron: 32 faces, 30 vertices, and 60 edges.
%C Height of a regular pentagon with side length 1. - _Jared Kish_, Oct 16 2014
%C Volume of a regular decagonal prism with unit side length and height 2. - _Wesley Ivan Hurt_, May 04 2021
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/Icosidodecahedron.html">Icosidodecahedron</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/Pentagon.html">Pentagon</a>
%H <a href="/index/Al#algebraic_04">Index entries for algebraic numbers, degree 4</a>
%F Equals sqrt(5+2*sqrt(5))/2.
%e 1.53884176858762670128514528801845491200335107176889621351957812518743...
%p sqrt(5+2*sqrt(5.))/2
%t RealDigits[Sqrt[5+2Sqrt[5]]/2,10,120][[1]] (* _Harvey P. Dale_, Jun 23 2017 *)
%o (PARI) sqrt(5+2*sqrt(5))/2
%Y Cf. A010527, A102208, A179290, A179292, A179294, A179449, A179450, A179451.
%K nonn,cons,easy
%O 1,2
%A _Vladimir Joseph Stephan Orlovsky_, Jul 14 2010
%E Partially rewritten by _Charles R Greathouse IV_, Feb 03 2011
%E Edited by _M. F. Hasler_, Oct 16 2014
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