A232811 - OEIS

%I #15 Aug 21 2023 11:40:13

%S 5,7,1,9,1,0,5,7,5,7,9,8,1,6,1,9,4,4,2,5,4,4,4,5,3,9,7,2,3,9,6,5,6,2,

%T 9,4,6,6,3,7,4,4,2,5,6,7,9,0,2,0,8,1,2,3,9,6,5,5,8,5,7,2,4,1,5,5,2,5,

%U 0,7,1,7,4,3,8,6,1,7,0,2,4,8,0,4,1,8,1,1,4,3,0,3,9,2,0,8,1,6,7,7,6,5,3,2,3

%N Decimal expansion of the surface index of a regular octahedron.

%C Equivalently, the surface area of a regular octahedron with unit volume. Among Platonic solids, surface indices decrease with increasing number of faces: A232812 (tetrahedron), 6.0 (cube = hexahedron), this one, A232810 (dodecahedron), and A232809 (icosahedron).

%C An algebraic integer of degree 6 with minimal polynomial x^6 - 34992. - _Charles R Greathouse IV_, Apr 25 2016

%H Stanislav Sykora, <a href="/A232811/b232811.txt">Table of n, a(n) for n = 1..1000</a>

%H Wikipedia, <a href="http://en.wikipedia.org/wiki/Platonic_solid">Platonic solid</a>

%H <a href="/index/Al#algebraic_06">Index entries for algebraic numbers, degree 6</a>

%F sqrt(3)*6^(2/3).

%F A010469/A131594^(2/3).

%e 5.7191057579816194425444539723965629466374425679...

%t RealDigits[Sqrt[3]Surd[36,3],10,120][[1]] (* _Harvey P. Dale_, Mar 12 2015 *)

%o (PARI) sqrtn(34992,6) \\ _Charles R Greathouse IV_, Apr 25 2016

%Y Cf. A010469, A131594, A232808 (surface index for a sphere), A232809, A232810, A232812.

%K nonn,cons,easy

%O 1,1

%A _Stanislav Sykora_, Dec 01 2013