OFFSET
0,2
MAPLE
b := binomial; f2 := n->if n mod 2 = 0 then 2*add(floor(b(n, w)/(2*w+1)), w=0..n/2-1)+floor(b(n, n/2)/(n+1)); else 2*add(floor(b(n, w)/(2*w+1)), w=0..(n-1)/2); fi;
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Jul 07 2003
STATUS
approved