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Search: id:A085569
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| A085569 |
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Denominator of 2*Sum(C(n,w)/(2*w+1),w=0..n/2-1)+C(n,n/2)/(n+1) if n is even, or of 2*Sum(C(n,w)/(2*w+1),w=0..(n-1)/2) if n is odd. |
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+0
2
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| 1, 1, 3, 1, 15, 3, 7, 15, 45, 5, 231, 21, 455, 315, 45, 3, 1683, 3465, 7315, 5005, 3003, 143, 13455, 585, 6825, 13923, 3213, 6545, 515185, 17765, 110143, 31977, 2078505, 62985, 1789515, 51129, 210197, 426075, 246675, 6325, 1400355, 34155, 41612175, 84192075
(list; graph; listen)
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OFFSET
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0,3
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EXAMPLE
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1, 2, 8/3, 4, 88/15, 28/3, 104/7, 376/15, 1904/45, 372/5, 30152/231, ...
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MAPLE
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b := binomial; f1 := n->if n mod 2 = 0 then 2*add(b(n, w)/(2*w+1), w=0..n/2-1)+b(n, n/2)/(n+1); else 2*add(b(n, w)/(2*w+1), w=0..(n-1)/2); fi;
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CROSSREFS
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Cf. A085568-A086673.
Sequence in context: A108083 A134145 A134146 this_sequence A072479 A131440 A119301
Adjacent sequences: A085566 A085567 A085568 this_sequence A085570 A085571 A085572
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KEYWORD
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nonn,frac
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AUTHOR
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njas, Jul 07 2003
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