A137915 Decimal expansion of 180*arccos(1/3)/Pi.

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

Offset

2,1

Comments

Dihedral angle in degrees of regular tetrahedron.

Polar angle (or apex angle) of the cone that subtends exactly one third of the full solid angle. - Stanislav Sykora, Feb 20 2014

Links

G. C. Greubel, Table of n, a(n) for n = 2..10001

Frank Jackson and Eric W. Weisstein, Tetrahedron

Eric Weisstein's World of Mathematics, Dihedral Angle

Formula

180*A137914/Pi = 180*arccos(1/3)/Pi.

Example

70.52877936550930863075400066003756403699315689909205171182889364396025356...

Mathematica

RealDigits[180 ArcCos[1/3]/Pi, 10, 120][[1]] (* Harvey P. Dale, Jul 13 2013 *)

Prog

(PARI) 180*acos(1/3)/Pi
(Magma) SetDefaultRealField(RealField(100)); R:= RealField(); 180*Arccos(1/3)/Pi(R); // G. C. Greubel, Aug 20 2018

Crossrefs

Cf. A137914 (same in radians).

Sequence in context: A033150 A064648 A116198 * A316167 A272037 A309724

Adjacent sequences: A137912 A137913 A137914 * A137916 A137917 A137918

Keyword

cons,nonn

Author

Rick L. Shepherd, Feb 22 2008

Status

approved