A395166 - OEIS

A395166

Decimal expansion of the midradius of an uniform 9-gonal antiprism with unit edges.

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

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OFFSET

1,2

LINKS

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

Polytope Wiki, Enneagonal antiprism.

Eric Weisstein's World of Mathematics, Antiprism.

Wikipedia, Antiprism.

Index entries for algebraic numbers, degree 3.

FORMULA

Equals csc(Pi/18)/4 = 1/(4*sin(Pi/18)) = 1/(4*A019819).

Equals A019879 + 1/2.