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A179294 Decimal expansion of radius of inscribed sphere about a regular icosahedron with edge = 1. 26
7, 5, 5, 7, 6, 1, 3, 1, 4, 0, 7, 6, 1, 7, 0, 7, 3, 0, 4, 8, 0, 1, 3, 3, 7, 0, 2, 0, 2, 5, 0, 0, 1, 3, 9, 2, 6, 3, 8, 4, 4, 4, 7, 8, 8, 8, 9, 3, 5, 6, 1, 0, 5, 9, 2, 2, 9, 5, 8, 2, 8, 9, 2, 0, 3, 9, 1, 0, 6, 8, 4, 5, 2, 2, 1, 9, 4, 8, 2, 6, 2, 0, 6, 3, 5, 6, 0, 4, 9, 4, 7, 6, 0, 8, 6, 8, 2, 7, 0, 4, 1, 1, 9, 3, 1 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET
0,1
COMMENTS
Icosahedron: A three-dimensional figure with 20 equilateral triangle faces, 12 vertices, and 30 edges.
LINKS
Dr. Math, Icosahedron
Wikipedia, Icosahedron
MathWorld, Icosahedron
FORMULA
Sqrt(42 + 18*sqrt(5))/12.
EXAMPLE
0.75576131407617073048013370202500139263844478889356105922958289203910...
MATHEMATICA
a=1; RealDigits[N[(Sqrt[42+18Sqrt[5]]/12)*a, 175]]
CROSSREFS
Cf. Platonic solids inradii: A020781 (tetrahedron), A020763 (octahedron), A237603 (dodecahedron).
Sequence in context: A226580 A182007 A247320 * A259679 A247876 A011474
KEYWORD
nonn,cons,easy
AUTHOR
EXTENSIONS
Partially rewritten by Charles R Greathouse IV, Feb 03 2011
STATUS
approved

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Last modified March 19 04:58 EDT 2024. Contains 370952 sequences. (Running on oeis4.)