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Search: id:A159605
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| A159605 |
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E.g.f: Sum_{n>=1} a(n)*x^(2n-1)/(2n-1)! = Series_Reversion of e.g.f. S(x) of A159601. |
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+0
1
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| 1, 3, 63, 3465, 363825, 62214075, 15740160975, 5524796502225, 2569030373534625, 1528573072253101875, 1132672646539548489375, 1022803399825212285905625, 1105650475211054481063980625, 1409704355894094463356575296875
(list; graph; listen)
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OFFSET
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1,2
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FORMULA
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a(n) = Product_{k=1..n} (2k-3)(4k-5).
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EXAMPLE
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E.g.f.: A(x) = x + 3*x^3/3! + 63*x^5/5! + 3465*x^7/7! +...
A(S(x)) = x where S(x) = Sum_{n>=1} A159601(n)*x^(2n-1)/(2n-1)! :
S(x) = x - 3*x^3/3! + 27*x^5/5! - 441*x^7/7! + 11529*x^9/9! +...
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PROGRAM
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(PARI) a(n)=prod(k=1, n, (2*k-3)*(4*k-5))
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CROSSREFS
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Cf. A159601.
Sequence in context: A139293 A133275 A123687 this_sequence A156904 A053857 A037108
Adjacent sequences: A159602 A159603 A159604 this_sequence A159606 A159607 A159608
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KEYWORD
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nonn
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AUTHOR
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Paul D. Hanna (pauldhanna(AT)juno.com), May 11 2009
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