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A358361
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Decimal expansion of the constant Sum_{j>=0} j!!/(2*j)!, where j!! indicates the double factorial of j.
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0
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1, 5, 8, 7, 7, 0, 2, 6, 4, 7, 7, 2, 7, 6, 6, 0, 5, 0, 7, 9, 7, 1, 8, 0, 1, 2, 6, 6, 2, 8, 5, 5, 5, 3, 7, 3, 2, 2, 3, 5, 4, 8, 6, 2, 3, 2, 4, 6, 7, 7, 2, 1, 2, 5, 2, 7, 5, 1, 6, 3, 2, 0, 4, 7, 3, 5, 6, 6, 5, 1, 0, 4, 0, 4, 6, 7, 1, 8, 6, 9, 5, 4, 9, 5, 5, 2, 2
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OFFSET
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1,2
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COMMENTS
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Sum_{j>=0} j!!/(2j)! converges since Sum_{j>=0} j!!/j! converges by A143280 (and it is trivial to note that (2*j)! >= j! for any positive integer j).
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LINKS
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FORMULA
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Equals Sum_{j>=0} 1/(A264152(j)*j!).
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EXAMPLE
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1.587702647727...
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MATHEMATICA
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RealDigits[1 + Sum[(i)!!/(2i)!, {i, 1, 200}], 10, 105][[1]]
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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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