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A086465
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Decimal expansion of (5 + 4*sqrt(5)*arcsch(2))/25.
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5
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3, 7, 2, 1, 6, 3, 5, 7, 6, 3, 8, 5, 6, 0, 1, 6, 1, 5, 5, 5, 5, 7, 7, 3, 2, 9, 3, 1, 8, 0, 2, 4, 2, 1, 7, 0, 1, 6, 9, 8, 2, 8, 2, 7, 3, 0, 1, 6, 1, 1, 5, 8, 6, 1, 9, 0, 2, 8, 0, 2, 4, 4, 1, 5, 9, 7, 0, 2, 4, 4, 8, 6, 1, 8, 4, 4, 5, 2, 7, 8, 4, 5, 4, 4, 5, 9, 6, 1, 0, 5, 8, 7, 8, 8, 8, 7, 9, 8, 2
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OFFSET
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0,1
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LINKS
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FORMULA
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Equals Sum_{n>=1} (-1)^(n-1)/binomial(2*n,n).
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EXAMPLE
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0.37216357638560161555577...
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MAPLE
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2/625*(14*sqrt(5)*log((1+sqrt(5))/2)+5) ; # R. J. Mathar, Mar 04 2009
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MATHEMATICA
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RealDigits[(5 + 4*Sqrt[5]*ArcSinh[1/2])/25, 10, 120][[1]] (* Amiram Eldar, May 25 2023 *)
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PROG
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(PARI) suminf(n=1, (-1)^(n-1)/binomial(2*n, n)) \\ Michel Marcus, Jul 31 2015
(PARI) asinh(.5)*sqrt(5)*.16+.2 \\ Use \p99 to get 99 digits. - M. F. Hasler, Jul 31 2015
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CROSSREFS
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KEYWORD
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AUTHOR
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EXTENSIONS
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Corrected definition and digits by a factor of 25/24. - R. J. Mathar, Mar 04 2009
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STATUS
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approved
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