This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A085573 #4 Mar 30 2012 16:49:45 %S A085573 2,6,11,20,32,56,97,172,298,534,952,1736,3150,5824,10724,20042,37308, %T A085573 70304,131971,250308,473020,901872,1713596,3281122,6262254,12033330, %U A085573 23053047,44431308,85393280,165008114,318009610,615878180,1189803926,2308781688 %N A085573 2*Sum(floor(C(n,w)/w),w=1..n/2-1)+floor(C(n,n/2)/(n/2)) if n is even, otherwise 2*Sum(floor(C(n,w)/w),w=1..(n-1)/2). %p A085573 b := binomial; f3 := n->if n mod 2 = 0 then 2*add(floor(b(n,w)/w),w=1..n/2-1)+floor(b(n,n/2)/(n/2)); else 2*add(floor(b(n,w)/w),w=1..(n-1)/2); fi; %Y A085573 Cf. A085568-A086672. %K A085573 nonn %O A085573 2,1 %A A085573 _N. J. A. Sloane_, Jul 07 2003