Dear seqfans with Mathematica (or other tools?!), anyone may wish to check this strange result: FullSimplify[Sum[(1/i)*Binomial[2n-i-1,i-1],{i,1,n}]] = (2^(-1 - 2*n)*(-4^n + (1 + Sqrt[5])^(2*n)))/n I use M 5.1. Thanks, Zak