A380703 Decimal expansion of the obtuse vertex angle, in radians, in a (small) triakis octahedron face.

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

Offset

1,1

Links

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

Wikipedia, Triakis octahedron.

Formula

Equals arccos(1/4 - sqrt(2)/2) = arccos(1/2 + A010503).

Equals Pi - 2*A380702.

Example

2.045535838349167749400916817638245527237744672...

Mathematica

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

Crossrefs

Cf. A380702 (face obtuse angles).

Cf. A010503, A378351, A378352, A378353, A378354.

Sequence in context: A376660 A329233 A111677 * A326186 A387517 A326055

Adjacent sequences: A380700 A380701 A380702 * A380704 A380705 A380706

Keyword

nonn,cons,easy

Author

Paolo Xausa, Jan 30 2025

Status

approved