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A208899
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Decimal expansion of sqrt(5)/3.
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3
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7, 4, 5, 3, 5, 5, 9, 9, 2, 4, 9, 9, 9, 2, 9, 8, 9, 8, 8, 0, 3, 0, 5, 7, 8, 8, 9, 5, 7, 7, 0, 9, 2, 0, 7, 8, 4, 8, 0, 2, 0, 6, 1, 1, 9, 8, 7, 0, 5, 0, 8, 5, 7, 4, 7, 5, 6, 9, 6, 5, 7, 4, 8, 4, 7, 0, 1, 7, 3, 6, 4, 1, 8, 7, 9, 2, 6, 8, 2, 9, 9, 8, 0, 4, 8, 0, 4, 8, 0, 2, 7, 9, 2, 9, 2, 7, 4, 2, 4, 9
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OFFSET
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0,1
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COMMENTS
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Equals the absolute value of the cosine of the dihedral angle between two adjacent faces of the regular icosahedron.
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LINKS
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FORMULA
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Equals Sum_{k>=0} (-1)^k * binomial(2*k,k)/5^k. - Amiram Eldar, Aug 03 2020
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EXAMPLE
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0.7453559924...
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MATHEMATICA
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PROG
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(PARI) first(n) = default(realprecision, max(28, n+10)); digits(((sqrt(5)/3)*10^n)\1) \\ David A. Corneth, Dec 19 2022
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CROSSREFS
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KEYWORD
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AUTHOR
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STATUS
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approved
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