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A086467
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Decimal expansion of 2*arccsch(2)^2.
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5
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4, 6, 3, 1, 2, 9, 6, 4, 1, 1, 5, 4, 3, 8, 8, 7, 8, 4, 9, 9, 3, 8, 5, 8, 1, 4, 2, 4, 6, 3, 0, 6, 5, 5, 2, 0, 0, 3, 2, 8, 1, 2, 7, 0, 0, 0, 9, 8, 5, 9, 7, 7, 4, 1, 6, 3, 0, 6, 0, 2, 4, 5, 7, 3, 7, 9, 5, 9, 0, 6, 9, 1, 1, 3, 3, 9, 2, 3, 6, 2, 5, 9, 7, 0, 1, 0, 9, 0, 9, 4, 1, 7, 2, 7, 7, 6, 7, 9, 0, 1, 1, 1
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OFFSET
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0,1
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LINKS
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Steven R. Finch, Mathematical Constants II, Encyclopedia of Mathematics and Its Applications, Cambridge University Press, Cambridge, 2018, p. 77.
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FORMULA
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Equals Sum_{n>=1} (-1)^(n-1)/n^2/binomial(2*n,n).
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EXAMPLE
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0.4631...
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MATHEMATICA
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RealDigits[2ArcCsch[2]^2, 10, 120][[1]] (* Harvey P. Dale, Mar 07 2012 *)
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PROG
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(PARI) suminf(n=1, (-1)^(n-1)/n^2/binomial(2*n, n)) \\ Michel Marcus, Jul 31 2015
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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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