A387148 - OEIS

A387148

Decimal expansion of the largest dihedral angle, in radians, in a gyroelongated square pyramid (Johnson solid J_10).

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

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OFFSET

1,1

COMMENTS

This is the dihedral angle between a triangular face in the square pyramid part and a triangular face in the square antiprism part of the solid.

Also the analogous dihedral angle in a gyroelongated square bipyramid (Johnson solid J_17).

LINKS

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

Wikipedia, Gyroelongated square bipyramid.

Wikipedia, Gyroelongated square pyramid.

FORMULA

Equals arccos((1 - sqrt(2) - 2*2^(1/4))/3) = arccos((1 - A002193 - A011027)/3).