A380793 Decimal expansion of the acute vertex angles, in radians, in a triakis icosahedron face.

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

Offset

0,1

Comments

A triakis icosahedron face is an isoscele triangle with two acute angles (this constant) and one obtuse angle (A380794).

Links

Paolo Xausa, Table of n, a(n) for n = 0..10000

Eric Weisstein's World of Mathematics, Triakis Icosahedron.

Wikipedia, Triakis icosahedron.

Formula

Equals arccos((A001622 + 7)/10).

Equals (Pi - A380794)/2.

Example

0.5319820207419660956392085612923249382641913791392...

Mathematica

First[RealDigits[ArcCos[(GoldenRatio + 7)/10], 10, 100]]

Crossrefs

Cf. A001622, A378973, A378974, A378976, A378977, A380794.

Sequence in context: A262674 A011363 A021192 * A074396 A391959 A383186

Adjacent sequences: A380790 A380791 A380792 * A380794 A380795 A380796

Keyword

nonn,cons,easy

Author

Paolo Xausa, Feb 04 2025

Status

approved