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Search: id:A028339
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| A028339 |
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Coefficient of x^2 in expansion of (x+1)(x+3)...(x+2n-1). |
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+0
5
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| 1, 9, 86, 950, 12139, 177331, 2924172, 53809164, 1094071221, 24372200061, 590546123298, 15467069396610, 435512515705695, 13121113142970855, 421214220916438680, 14354510691610713240, 517596339235489288425
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OFFSET
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2,2
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FORMULA
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sum[(-1)^(k+1-i) 2^(n-1) binomial(i-1, k) s1(n, i), i=k+1..n] with k = 2, where s1(n, i) are unsigned Stirling numbers of the first kind - Victor Adamchik (adamchik(AT)ux10.sp.cs.cmu.edu), Jan 23, 2001
E.g.f.: 1/8*(1-2*x)^(-1/2)*ln(1-2*x)^2. - Vladeta Jovovic (vladeta(AT)eunet.rs), Feb 19 2003
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CROSSREFS
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Cf. A028338.
Contribution from Johannes W. Meijer (meijgia(AT)hotmail.com), Jun 08 2009: (Start)
Equals third left hand column of A161198 triangle divided by 4.
(End)
Sequence in context: A029711 A015581 A152261 this_sequence A100814 A055725 A144852
Adjacent sequences: A028336 A028337 A028338 this_sequence A028340 A028341 A028342
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KEYWORD
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nonn
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AUTHOR
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R. W. Gosper
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