A380701 Decimal expansion of the obtuse vertex angle, in radians, in a triakis tetrahedron face.
1, 9, 7, 0, 2, 2, 1, 5, 6, 6, 6, 7, 5, 4, 9, 1, 3, 1, 9, 2, 2, 7, 1, 2, 8, 3, 0, 6, 3, 2, 4, 4, 6, 7, 3, 5, 1, 7, 9, 6, 4, 4, 7, 2, 6, 5, 0, 3, 1, 8, 2, 2, 8, 1, 5, 6, 7, 3, 8, 2, 5, 9, 3, 7, 8, 6, 5, 2, 8, 6, 5, 6, 2, 0, 1, 9, 7, 2, 8, 3, 2, 0, 9, 8, 4, 0, 2, 9, 5, 5
Offset: 1
Examples
1.9702215666754913192271283063244673517964472650318...
Links
- Paolo Xausa, Table of n, a(n) for n = 1..10000
- Wikipedia, Triakis tetrahedron.
Programs
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Mathematica
First[RealDigits[ArcCos[-7/18], 10, 100]]
Formula
Equals arccos(-7/18).
Equals Pi - 2*A380700.