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A085571
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Numerator of 2*Sum(C(n,w)/w,w=1..n/2-1)+C(n,n/2)/(n/2) if n is even otherwise of 2*Sum(C(n,w)/w,w=1..(n-1)/2).
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0
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2, 6, 11, 20, 101, 175, 593, 173, 1502, 2684, 28649, 52169, 662393, 1224077, 4506259, 4210067, 23506871, 44294491, 41572193, 78849257, 1639049932, 3125022742, 23750582143, 9095291663, 225666905951, 144544431373, 276913262539, 76244134117, 732674442397
(list; graph; refs; listen; history; internal format)
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OFFSET
| 2,1
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EXAMPLE
| 2, 6, 11, 20, 101/3, 175/3, 593/6, 173, 1502/5, 2684/5, 28649/30, ...
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MAPLE
| b := binomial; f3 := n->if n mod 2 = 0 then 2*add(b(n, w)/w, w=1..n/2-1)+b(n, n/2)/(n/2); else 2*add(b(n, w)/w, w=1..(n-1)/2); fi;
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CROSSREFS
| Cf. A085568-A086673.
Sequence in context: A085573 A171516 A081691 * A007684 A135348 A083322
Adjacent sequences: A085568 A085569 A085570 * A085572 A085573 A085574
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KEYWORD
| nonn,frac
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), Jul 07 2003
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