A380704 Decimal expansion of the acute vertex angles, in radians, in a deltoidal icositetrahedron face.

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

Offset: 1

Author

Paolo Xausa, Jan 31 2025

Keywords

• nonn
• cons
• easy

Examples

			1.4238211361313915494455573566669046848857979902951...
		

Links

• Paolo Xausa, Table of n, a(n) for n = 1..10000
• Wikipedia, Deltoidal icositetrahedron.

Crossrefs

Cf. A380705 (obtuse face angle).

Cf. A020765, A378390, A378391, A378392, A378393, A378394.

Programs

Mathematica

First[RealDigits[ArcCos[1/2 - Sqrt[2]/4], 10, 100]]

Formula

Equals arccos(1/2 - sqrt(2)/4) = arccos(1/2 - A020765).

Equals (2*Pi - A380705)/3.