A378204 - OEIS

%I #13 Feb 11 2025 14:40:12

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

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

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

%N Decimal expansion of the surface area of a triakis tetrahedron with unit shorter edge length.

%C The triakis tetrahedron is the dual polyhedron of the truncated tetrahedron.

%H Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/TriakisTetrahedron.html">Triakis Tetrahedron</a>.

%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Triakis_tetrahedron">Triakis tetrahedron</a>.

%H <a href="/index/Al#algebraic_02">Index entries for algebraic numbers, degree 2</a>.

%F Equals (5/3)*sqrt(11) = (5/3)*A010468.

%e 5.5277079839256664151915545611178111398784809093...

%t First[RealDigits[5*Sqrt[11]/3, 10, 100]] (* or *)

%t First[RealDigits[PolyhedronData["TriakisTetrahedron", "SurfaceArea"], 10, 100]]

%Y Cf. A378205 (volume), A378206 (inradius), A378207 (midradius), A378208 (dihedral angle).

%Y Cf. A377274 (surface area of a truncated tetrahedron with unit edge).

%Y Cf. A010468.

%K nonn,cons,easy

%O 1,1

%A _Paolo Xausa_, Nov 20 2024