A380863 Decimal expansion of the obtuse vertex angle, in radians, in a deltoidal hexecontahedron face.

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

Offset

1,1

Comments

A deltoidal hexecontahedron face is a kite with one smallest acute angle (A380861), two largest acute angles (A380862) and one obtuse angle (this constant).

Links

Paolo Xausa, Table of n, a(n) for n = 1..10000

Wikipedia, Deltoidal hexecontahedron.

Formula

Equals arccos((-5 - 2*sqrt(5))/20) = arccos((-5 - 2*A002163)/20).

Equals 2*Pi - A380861 - 2*A380862.

Example

2.0641778238390721349307678649869730069970513653...

Mathematica

First[RealDigits[ArcCos[(-5 - 2*Sqrt[5])/20], 10, 100]]

Crossrefs

Cf. A002163, A379385, A379386, A379387, A379388, A379389, A380861, A380862.

Sequence in context: A291240 A233207 A136656 * A256850 A242561 A372767

Adjacent sequences: A380860 A380861 A380862 * A380864 A380865 A380878

Keyword

nonn,cons,easy,new

Author

Paolo Xausa, Feb 07 2025

Status

approved