A085571 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).

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

Offset: 2

Author

N. J. A. Sloane, Jul 07 2003

Keywords

• nonn
• frac

Examples

			2, 6, 11, 20, 101/3, 175/3, 593/6, 173, 1502/5, 2684/5, 28649/30, ...
		

Crossrefs

Cf. A085568-A086673.

Programs

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;