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Search: id:A074799
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| A074799 |
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a(1)=1; for n>1, a(n) is the numerator of b(n) = (4*n+1)*(prod(i=1,n,2*i-1)/prod(i=1,n,2*i))^5. |
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+0
2
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| 1, 5, 2187, 40625, 892871875, 20841167403, 16443713753775, 421390226721321, 364130196991193221875, 9816949116755633084375, 8619392462988365485907909, 239904481399203205153660455
(list; graph; listen)
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OFFSET
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0,2
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REFERENCES
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Bruce C. Berndt and Robert Rankin,"Ramanujan : letters and commentary", AMS-LMS, History of mathematics vol. 9, p. 57
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FORMULA
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1+sum(k>=1, (-1)^k*b(k))=2/gamma(3/4)^4=0.88694116857811540541...
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PROGRAM
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(PARI) a(n)=numerator((4*n+1)*(prod(i=1, n, 2*i-1)/prod(i=1, n, 2*i))^5)
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CROSSREFS
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Cf. A074800.
Sequence in context: A105035 A004816 A114428 this_sequence A067944 A114716 A036772
Adjacent sequences: A074796 A074797 A074798 this_sequence A074800 A074801 A074802
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KEYWORD
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easy,frac,nonn
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AUTHOR
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Benoit Cloitre (benoit7848c(AT)orange.fr), Sep 08 2002
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